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MY Yasin, C Koch-Hofer, Pascal Vivet, DJ Greaves . TLM Power 3.0

1. Figure 3 Energy based instrumentation of TLM call intra module component The power values associated to a power mode can also be accessed through the GET_DYNAMIC_POWER and the GET STATIC POWER methods For example these methods can be used with the basic methods of the class pw module for describing the complex part of a power behavior and still using the method UPDATE POWER for the simple part 2 13 Logging Power Consumption Transaction Energy Approach Power consumption associated with a transaction consists of two components 1 Inter module power proportional to wiring length and number of bits in tran sistion 2 Intra module power associated with internal operation inside the component Figure 3 is a simple illustration of the the approach where transactional energy consumption internal to a module is logged for each transaction For each trans action the transport method logs both the intra module energy consumed and the activity time for which is has been busy The cost per bit is multiplied by the transaction length to model its dynamic energy use This energy is is passed to update energy as the first argument where it is TLM Power 3 0 CBG User Manual 14 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves trans pw_set_origin this PW_TGP_ADDRESS PW_TGP_ACCT_SRC amp frontside_bus initiator_socket gt b_transport trans delay tra
2. void process void update_power PW_MODE_ON PW_PHASE_IDLE wait 10 SC NS Perform some computation update power PW MODE ON PW PHASE COMPUTE wait 20 SC NS update power PW MODE OFF Turn off module Figure 10 mode phase style annotation example based on pw module 7 2 DMI Callbacks Power consumption is not accurately modelled when DMI is in use The library has an invalidate hook that can be used to si 8 Modelling Example TAC Simple Basic Platform The presented modelling facilities were used to model the power behavior of a simple TAC platform Figure B This platform is composed of a first traffic generator MASTER1 which perform memory accesses to the RAM1 The second traffic generator MASTER2 peri odically initializes a TIMER and waits for its interrupt All these components except the interrupt signal communicate via a TAC MULTIPORT ROUTER All the components of this platform were instrumented with timing and power annotations For instance the transport method of the TAC MULTIPORT ROUTER was instrumented TLM Power 3 0 CBG User Manual Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f 26 MY Yasin C Koch Hofer Pascal Vivet DJ Greaves tac response tac multiport router transport t ifdef TLM POWERS static unsigned 1 nb transaction 0 l nb transaction pw_power 1 dynamic pwr request get number get dynamic power ON ROUTE pw_power l s
3. 5 File Formats that are supported in Excel http office microsoft com en us excel HP100141031033 aspx TODO mention PlotCombinedAccounts for VCD tracing mention title mention CSV output mention plt variation on vcd TLM Power 3 0 CBG User Manual 32 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f
4. ROUTE 3 100E 08j 2214E 01w 70 76096 1 400E 10j 1 000E 03w 9 85296 MASTER1 4 109E 08 2 892E 02w 14 652 3 A40E 10j 2 421E 04w 4618 ON 4 109E 08j 1 194E 01w 100 000 3 440E 10j 1 000E 03w 100 000 COMMUNICATE 1 430E 09j 1J000E 02w 3 480 1 430E 10j 1 000E 03w 41 57096 COMPUTE 3 960E 08j 2 000E 01w 96 374 1 980E 10 1 000E 03w 57 558 INIT 6 000E 11j 2 000E 02w 0 146 3 DODE 12j 1 00DE 03w 0 872 MASTER2 3 432E 08j 2415E 02w 12 238 1 421E 09j 1 000E 03w 19 076 ON 3 432E 08 2 415E 02w 100 000 1 421E 08j 1 000E 03w 100 00096 CHECK 2 240E 10j 4 000E 03w 0 653 5 600E 11 1 Q00E 03w 3 941 COMMUNICATE 4 900E 10j 1 000E 02w 1 428 4 900E 11j 1 Q00E 03w 3 448 COMPUTE 3 210E 08j 5 000E 02w 93 534 6 420E 10 1 Q00E 03w 45 17996 IDLE 5 790E 10j 1 O00E 03w 1687 5 790E 10j 1 Q0DE 03w 40 7 4696 INIT 5 DDDE 12j 2 000E 03w 0 017 3 000E 12j 1 000E 03w 0 211 INTERRUPT 9 200E 10 1 000E 02w 2 681 9 200E 11j 1 Q00E 03w 6 47495 TIMER 4 268E 09j 3 004E 03w 1522 1 421E 09j 1 000E 03w 19 076 ON 4 268E 09 3 004E 03w 100 000 1 421E 09j 1 Q00E 03w 100 000 IDLE 1 193E 09j 1 000E 03w 27 952 1 193E 09j 1 Q00E 03w 83 955 INTERRUPT 4 950E 10j 5 000E 03w 11 598 9 900E 11j 1 QODE 03w 6 967 WRITE 2 580E 09j 2 DODE 02w 60 450 1 290E 10j 1 Q00E 03w 9 078 M 4 gt gt i power_trace result Is D NUM Pr t D marrer Ba Sex oe ZACHP201ADOCIWG M 4 tlm_power2 manual doc 38 Microsoft Excel pow Figure 8 S
5. physical size parameters bit width number of words and so on and it should can use these in setting its placement and power profile These instantantiations parameters can be combined with values read from a technology instance file and supply voltage settings to determine standing powers and transaction energies 2 9 Technology Instance configuration file Components that inherit pv module may import a technology instance configura tion file to assist with setting their physical size allocating power consumption to transactions and naming different power modes and phases Normally a defaulting value for the name of the file to be read is given by the Sys temC kind of the component The default name is power config modulekind txt where modulekind is the kind identifier This approach is suitable where all of the per instance variations are controlled by the constructor of the SC MODULE and nothing needs reading from the configuration file on a per instance basis Values read from the file can be modified by the constructor using for instance other parameters read from user globals or module parameters such as the size of a RAM When the pw module constructor is called with no arguments the module should implement the kind method i e module type name that returns a constant string whose name is used as the basis for the file to be consulted The name of the file to read can alternatively be specified as an argument t
6. square This is a simplistic approach which is correct in terms of area but not suitable for physical manufacture A png plot file is created for the placement to help visualisation Wiring area An additional wiring swell is added to the area of each component based on the number of internal connections it has Internal connections may be sc signals or TLM sockets or user defined Geometric Wiring distance Using geometric modelling the wiring length be tween two components is computed as the Manhattan distance between their cen tres Rentian Wiring Distance Using rentian wiring 3 2 TLM Wiring Energy Modelling Given that a transaction takes place between two components that are part of a layout the distance information can be combined with the number of transition ing bits in an envisaged underlying bus implementation to compute the wiring energy associated with the transaction However there are a number of general considerations to including in a wiring energy model for TLM 1 Although a single transaction generic payload may typically be transferred on a round trip basis from originator through the bus NoC and server com ponents back to the originator not all fields will be active in the underlying bus implementation at each hop 2 Some hops may be off chip PCB traces with associated pads that have differ ent energy cost per unit length compared with on chip interconnects On chip connections are typically unidir
7. the power trace function Each item traced generates a fresh set of totals that include that item and in common use all of its children So the consumption of a component can be included in more than one trace total of a similar form by tracing it and one or more of its parents or by tracing two or more of its parents There are two main forms out output trace file Firstly a VCD 6 1 trace file recording the power variations along a simulation Secondly a textual file or a SYLK SYmbolic Link file gathering different statistics about the power and energy consumptions 6 1 VCD Traces AVCD trace file records a time ordered sequence of instantanious power values during sim ulation Energy plots would be monotonic and not that pretty so are not currently supported The VCD trace file can be created and opened by calling function pw_create_vcd_trace_file A trace file may be opened during elaboration or at any time during simulation Energy ob servers can be traced by calling function pw trace A trace file shall be opened before values can be traced to that file and values shall not be traced to a given trace file if one or TLM Power 3 0 CBG User Manual 22 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves Signals Waves p Time ATOP dyn 0 112 ROUTER dyn 0 01 TIMER dyn 0 001 MASTER2 dyn 0 001 MASTER1 dyn 0 Figure 7 TAC Power C
8. value with an incorrect unit Message Division by zero not allowed with pw energy Meaning Try to divide an energy value with zero Message Energy resolution can only be set during elaboration phase Meaning Call the SET ENERGY resolution during the simulation phase Message Energy resolution already fixed Meaning Call the SET ENERGY resolution function more than one time or after constructing a energy object different from zero Message Energy value must be positive Meaning Try to construct a energy object with a negative double parameter Message Overflow with energy resolution value Meaning The SET ENERGY resolution function was called with an incorrect double parameter greater than 294 1 or fewer than 1 0 Message Failed to initialize input stream Meaning The initialization of an input stream ENERGY_UNIT energy failed Message Failed to extract energy value from input stream Meaning The token of an input stream was not representing an energy value syntax error Message Failed to extract energy value from input stream Meaning The token of an input stream was not representing an energy unit value syntax error Message Division by zero not allowed Meaning Try to divide an energy value with a zero power or time value Message Overflow with pw module base ATTRIBUTE ID data Meaning Internal error code which should not happen Message Power module must
9. with pw_power data Arithmetic operation with power value has generated an underflow Message Meaning Overflow with pw_power_unit data Try to use or to perform some operation with invalid unit of power Message Meaning Overflow with pw_energy data Arithmetic operation with energy value has generated an overflow Message Meaning Underflow with pw_energy date Arithmetic operation with energy value has generated an underflow Message Meaning Overflow with pw_energy_unit data Try to use or to perform some operation with invalid unit of energy Message Meaning Redefinition of the power couple XXX XXX The same couple of power mode and power phase was defined more than one time in the same configuration file Message Meaning Reach end of infinite simulation without calling SC_STOP For properly generating the textual trace file the SystemC function SC_STOP shall be called at the end of the simulation Message Meaning Reach end of infinite simulation with non null power value XXX At the end of infinite simulation the module XXX has non null power value For preserving coherency the power consumption of this module will be calculated until the last power modification of the System TLM Power 3 0 CBG User Manual Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f 29 MY Yasin C Koch Hofer Pascal Vivet DJ Greaves TLM Power 3 0 CBG User M
10. DYNAMIC POWER DYNAMIC RATIO STATIC ENERGY STATIC POWER STATIC RATIO imi TOP 2 804E 07j 13874E 01w 100 000 7 449E 09j 5 242E 03w 100 000 MEMORY1 8 590E 08j 6 045E 02w 30 53196 1 421E 09j 1 Q00E 03w 19 076 MEMORY2 7 105E 08j 5 000E 02w 25 33596 1 421E 08j 1 Q00E 03w 18 076 ROUTER 4 381E 08j 3 083E 02w 15 622 1 421E 08j 1 00D0E 03w 19 076 MASTER1 4 109E 08j 2 892E 02w 14 652 3 440E 10j 2 421E 04w 4618 MASTER2 3 A32E 08j 2415E 02w 12 238 1 421E 09j 1 000E 03w 18 076 TIMER 4 268E 09j 3 004E 03w 1 522 1 421E 08j 1 000E 03w 19 076 TOTAL 2 B04E 07j 1 974E O1w 100 000 7 A49E 09j 5 242E 03w 100 000 MODULE NAME MODE NAME PHASE NAME DYNAMIC ENERGY DYNAMIC POWER DYNAMIC RATIO STATIC ENERGY STATIC POWER STATIC RATIO MEMORY1 8 590E 08j 6 045E 02w 30 53196 1 421E 08j 1 00DE 03w 19 076 ON 8 590E 08j 6 D045E 02w 100 000 1 421E 09j 1 000E 03w 100 000 IDLE 6 830E 08j 5 000E 02w 79 511 1 365E 09j 1 000E 03w 96 129 READ 4 A00E 09 2 000E 01w 5 122 2 200E 11j 1 00DE 03w 1 548 WRITE 1 320E 08j 4 000E 01w 15 367 3 300E 11j 1 000E 03w 2 322 MEMORY2 7 105E 08j 5 000E 02w 25 33596 1 421E 09j 1 OODE 03w 19 076 ON 7 105E 08j 5 00DE 02w 100 000 1 421E 08j 1 00D0E 03w 100 000 IDLE 7 105E 08j 5 000E 02w 100 00096 1 421E 08j 1 00DE 03w 100 000 ROUTER 4 381E 08j 3 083E 02w 15 622 1 421E 09j 1 000E 03w 19 076 ON 4 381E 08j 3 083E 02w 100 000 1 421E 08j 1 000E 03w 100 00096 IDLE 1 281E 08j 1 000E 02w 29 24096 1 281E 09 1 00DE 03w 90 148
11. Finally d11 gives some implementation information about this library 2 Power Modelling Versions 1 and 2 of the library were based on power mode phases for compo nents sleep standby active etc whereas version 3 adds support for energy per transaction logging Mode phase based approach The power consumption of a SystemC module is defined for each operation mode and modules switch between modes and phases throughout the simulation Energy per transaction approach SystemC modules log an energy quanta for each transaction they process based on computations of how much energy is used For instance for a bus the energy per transaction may include a component proportional to the burst length field in the generic payload The examples folder contains power3demo which uses the TLM generic payload and the energy logging approach The examples folder contains t1m tac which uses the mode phase approach This may no longer compiles properly in the pre beta release of the POWERS library 2 1 Customer Accounts New in release 3 1 is the customer id that is associated with a no children style Observer A customer identifier is created by a typical component such as a core but the observer will record energy credits from all over the system A customer identifier is declared as follows SC pwr pw customer id customer id constructor customer customer id sc module const char user name int idx 1 It is automatically ini
12. MY Yasin C Koch Hofer Pascal Vivet DJ Greaves TLM Power 3 0 CBG User Manual Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f TLM Power 3 0 CBG User Manual Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves March 17 2015 Contents 4 JA AGCOURIS cux eM ae ee a a a RLU 4 2 Power Modelling 7 2 1 Customer Accounts 0 a 7 2 2 Physical Data lypes 0000002 eee eee 8 2 3 Physical unit Power in Watts 2 8 2 4 Physical unit Energy inJoules 2040 9 2 Physical unit Length in Metres sosse os ss ss ss so os ve 9 TE 9 2 Physical unit Voltage in Volts soo os ss ss ss ss ss esse 9 2 8 Instrumenting a SystemC module 00 10 2 9 Technology Instance configuration file ss 10 2 10 ChiplRegion Name some see ee lll 11 2 11 VoltageScaling lll 12 2 12 Logging Power Consumption Mode Phase Approach 13 2 13 Logging Power Consumption Transaction Energy Approach 14 2 14 Logging Length and Areal como llle 15 MY Yasin C Koch Hofer Pascal Vivet DJ Greaves C 3 1 Place and Route Layout Distance and Bit Transition Modelling 3 2 TLM Wiring Energy Modelling lesse 3 3 TLM Wiring Energy Modelling Computation 3 4 TCM Wiring Energy Modelling Flags 3 5 Transi
13. YLK Statistics As presented in Figure 8 the statistics generated are the same as the one gathered in a textual trace file The first array gives the power consumption the energy consumption and the power contribution of each monitored modules The second array gives details about the power consumption of each module 7 Options 7 1 Net Transitions The net transition monitor may be enabled to compute the number of wires that change value in a transaction This behaviour typically follows well known patterns and so energy useage based on net transitions is not often required to be modelled However this facility helps calibrate and confirm such models TLM Power 3 0 CBG User Manual 25 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f 16 02 MY Yasin C Koch Hofer Pascal Vivet DJ Greaves tlm_power 2 0 est txt src include lib examples E pr cpp L h a tlm tac prod cons sh cpp wh README pe h README b c a gl doc ppt e test XXX README Figure 9 File Tree for a previous release lib and sh now do not exist class FOO public sc_module public pw_module t public SC HAS PROCESS FOO FOO const sc module name amp p_name sc_module p_name pw_module config txt SC_THREAD process
14. a PR_MICRON 40 PR_MICRON 40 0 25 Figure 6 Size Annotation Figure illustrates the basic approach to logging a component s area Although X Y dimensions are used to log area TLM POWERS assumes that a component can freely change its aspect ratio from 1 1 to 2 1 to obtain a good layout unless 3 Layout Distance and Bit Transition Modelling Both net level interconnects and TLM transactions model data moving some dis tance with associated charge and discharge of the nets It is important not to model both the charge and discharge of a given net otherwise energy costs will be double counted We adopt the approach of only counting the zero to one transition of a net as energy consuming 3 1 Place and Route Every component may compute and register its excess physical size in two dimen sions The excess size is how much more area the component has that the sum of its sub components A component may also register its absolute size in which case the sum of its components is ignored but a warning is issued if it behaves like a TARDIS having more internal size on the same chip than outside size Commonly some models will include components that do not physically exist inside them For instance a DRAM controller might instantiate the DRAM chips inside the controller rather than bothering to route the connections up through the top level of the SoC TLM POWERS supports this style of modelling using the concept of chip
15. a parameter of trace type Sc pwr trace t passed to the observer when it is attached in the pw trace call According to the value of this variable children can be disregarded or else included in the observer s accounts typedef enum i no children sum children also trace children trace t The third setting of the trace parameter creates multiple observers these being a standalone no children observer for the named module and independent stan dalone observers for all the children Signatures void pw trace pw trace file p file pt sc core sSc object amp p obj const std string amp p str trace t p do children no children void pw trace pw trace file p file pt sc_core sc_object amp p obj trace t p do children no children Example uses E txt pt pw create txt trace file g name Create an observer pw trace g txt pt the top also trace children Attach it to a modue pw trace g txt pt the top TOP ALIASNAME also trace children There is at most one observer of type summing and at most one observer of type standalone for each power module for each trace type The system itself also creates a top level grand total observer that totals the whole design whether or not such an observer is manually created The grand total obsever is a sum children observer that includes all power modules found from the SystemC top level We use the terms power module and component interchan
16. ange the state of any other component for which it has the C object pointer The state of the block is a pair that has phase and mode components There is no difference between phases and modes as far as the library is con cerned Phases are used to refer to short term functional phases of a component such as wait read and compute A mode is typically a particular DPM Dynamic Power Management mode such as on sleep or off Both are characterized by their standing power while in that mode phase and the time duration before the next mode phase is adopted To support monitoring the power consumption of any SystemC module the tracing facilities take advantage of the hierarchy of a SystemC model Indeed the energy logged by a module with a summing observer is equal to its own plus that of its sub modules down to the leaves of the module tree For example in Figure 1 the energy consumed by the module CLUSTERO is equal to the total of expended by its CPUs and its ROUTER The remainder of this document is organized as follows Section 2 presents how to model and instrument a TLM platform with power information Section 6 presents TLM Power 3 0 CBG User Manual 6 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves how to monitor and generate traces from an instrumented TLM platform Sec tion 3 describes the options relating to physical layout modelling and bit transition counting
17. anual Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f 30 MY Yasin C Koch Hofer Pascal Vivet DJ Greaves 12 2 Error Messages Message Overflow with pw power unit data Meaning Try to create a power value with an incorrect unit Message Division by zero not allowed with pw power Meaning Try to divide a power value with zero Message Power resolution can only be set during elaboration phase Meaning Call the SET POWER resolution during the simulation phase Message Power resolution already fixed Meaning Call the SET POWER resolution function more than one time or after constructing a power object different from zero Message Power value must be positive Meaning Try to construct a power object with a negative double parameter Message Overflow with power resolution value Meaning The SET POWER resolution function was called with an incorrect double parameter greater than 29 1 or fewer than 1 0 Message Failed to initialize input stream Meaning The initialization of an input stream POWER UNIT power failed Message Failed to extract power value from input stream Meaning The token of an input stream was not representing a power value syntax error Message Failed to extract power value from input stream Meaning The token of an input stream was not representing a power unit value syntax error Message Overflow with pw energy unit data Meaning Try to create an energy
18. ary implements classes that define units for manipulating power energy voltage length and area values 82 2 It also defines some base classes for defining the power consumption and the running mode of a module during a simulation 2 3 Physical unit Power in Watts Class PW POWER is used to represent electrical power value internal representa tion is internally a double and a PW_POWER_UNIT A pw power unit is an enumer ate type representing power physical unit pw W for femto watt pw pW for pico watt pw_WATT for watt The default power resolution is 1 pico watt The power resolution can only be changed by calling the function pw set power resolution double This function can only be called during elaboration cannot be called more than once and cannot be called after constructing an object of type pw power with a non zero power value The value of the double argument shall be positive and shall be a power of 10 A report of severity SC ERROR is thrown if these rules are not respected The value of the power resolution is given by the pw get power resolutionO function The constant pw ZERO POWER represents a power value of zero The static method max returns the maximal power value according to the power resolution All the traditional arithmetic relational equality and assignment operators are sup ported A report of severity SC WARNING or SC ERROR is thrown when the result of an arithmetic is not coherent When a
19. be an SC OBJECT Meaning Try to use the pw module or the pw module base class with an object not inheriting of the class SC OBJECT Message Unknown power mode failed to switch from XXX XXX to XXX XXX Meaning Call the UPDATE POWER method of the class pw module with power and or phase parameter not defined in the configuration file Message Failed to initialize output stream Meaning The initialization of an output stream ENERGY UNIT energy failed TLM Power 3 0 CB a M sead anualiled to open configuration file XXX YYY 1 Version CBG 3 2 Alphideaning Unable to open the configuration file XXX for the reason YYY DRAFT MANUAL URDAFEB 1Q r0 veReaue associated to the couple XXX XXX Meaning Internal error code which should not happen Message Svntay error on power value definition in file XXX at line YYY MY Yasin C Koch Hofer Pascal Vivet DJ Greaves Revision History Version 1 this library was developed by Hugo Lebreton for evaluating the power manage ment mechanisms designed for the Magali Platform 2 This first version was suffering from the following limitations 1 The power and energy value are defined by raw value which can lead to un debuggable errors for example mixing raw values using different implicit units e g milli watt and pico watt or types e g power and energy 2 The designer has to define intermediary classes and enumerated types for accessing an
20. c_pwr to the declarative region in which it is declared The file tree of the complete distribution is presented in Figure 9 At the top a README and a RELEASENOTE file briefly describe this library and how to use it The LICENSE file describes the licensing and contractual issues of the TLM POWER library The src and the include directories contain the source code of the library The static library version is located in the lib directory The simple TAC platform presented at felis located in the ex amples directory This directory also contains an example of a simple platform composed of a producer and a consumer exchanging messages This document an overview presen tation and a doxygen documentation of the source code can be found in the directory doc Finally the test directory contains a set of non regression tests 11 1 Compilation Modes The library can be compiled in verbose mode It can also be compiled in debug developer s mode This is conrolled by setting the relevant flags in the environment or at the top of the Makefile def if used or else as configure options TLM Power 3 0 CBG User Manual 28 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves 12 Messages 12 4 Warning Messages Message Meaning Overflow with pw_power data Arithmetic operation with power value has generated an overflow Message Meaning Underflow
21. ctual dimensions of current component void set fixed dimensions pw length x pw length y const char chipname 0 Set additional area of current component void set excess area pw length x pw length y float max aspect ratio 2 5 const char chipname 0 void set_excess_area pw_area a float max_aspect_ratio 2 5 const char chipname 0 The former sets the actual dimensions of the current component leading to a TARDIS warning if this is smaller than the sum of its components The excess area calls describe the additional area of the current component be yond that of the sum of its child components The component is assumed to be flexible in shape from square up to an oblong of maximum aspect ratio specified These calls also enable the chip region of the current component to be given If no name is given then the name of the instantiating parent is used At the top level if no name is give then the SystemC name is used TLM Power 3 0 CBG User Manual 15 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves class FOO public sc_module public pw_module public SC HAS PROCESS FOO FOO const sc module name p name int width sc module p name pw_module config txt set_excess_area pw_length 50 0 width PW_um pw_length 5 0 width PW_um or from tech file Figure 5 Length and area annotations pw_module pw_excess_are
22. d bus should be defined in the initiator class using Sc pwr tlm bit transition tracker forward bus and initialised in the constructor by passing it the this pointer of the initiating component Two calls to pw 1og hop are required in a passthrough component to register the forward and backward operations but flags and bus arguments are not normally needed see below TLM Power 3 0 CBG User Manual 20 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves Example code for a passthough TLM bus or NoC component void b_transport int id PW_TLM_PAYTYPE amp trans sc_time amp delay 1 h record energy use other code No special decorations are neede around the passthough operation passthrough init socket b transport trans delay other code trans pw_log_hop this h gt record_energy_use pw_handle h trans pw_log_hop this First call on entry to the component Second call at return operation the same handle will be returned and can be ignored The endpoint is much like a hop but this hop will generally change the active fields Also unless using tri states on a PCB a different bus should be provided to model separate read and write data busses in a SoC with different fields active and on a separate read bus tlm tlm command cmd trans get_command trans pw_log_hop this amp read_re
23. d on a per transaction basis it is appropriate to set the dynamic power of the mode phase to zero This can be achieved by simply not calling set_dynamic_power in that component The mode phase based power consumption of a component is normally announced by that component by calling one of the following convenience functions which de termine the current standing powers static and dynamic 1 the dynamic power consumption is set using SET_DYNAMIC_POWER PW_POWER amp 2 the static power consumption is set using SET STATIC POWER PW POWER amp 3 the mode of power consumption is set using SET POWER MODE STRING amp 4 the phase of the power mode consumption is set using SET POWER PHASE STRING amp 5 the phase and power mode can both be set at once using UPDATE POWER STRING amp MODE STRING amp PHASE Note that the full signature to SET STATIC POWER is void set static power const pw power amp int 1 acct PW ACCT STATIC DEFAULT and the body of SET DYNAMIC POWER does the same thing as SET STATIC POWER but with the account number being PW ACCT DYNAMIC DEFAULT Other ac count numbers may be freely used for other purposes The power mode and phase are strings used for associating a power consumption to any computation mode and phase of a module Some frequently used power modes and phases are pre defined PW MODE ON Pw MODE OFF PW PHASE WAIT The example in Figure presents how to associate different pow
24. d setting the power values of a SystemC module 3 The statistic module does not take into account the mode and phase For example it was the responsibility of the user intermediary classes to compute the global energy consumed by a module for different mode and phase 4 The power consumption of a module does not care about the consumption of its sub module It was not possible to automatically generate power information on the module CLUSTERO from its sub module Version 2 0 of this library was developed by C Koch Hofer Pascal Vivet at CEA to overcome these problems Version 3 0 CBG shifted the focus to energy based modelling of transactions and added physical distances References 1 H Lebreton and P Vivet Power Modeling in SystemC at Transaction Level Application to a DVFS Architecture IVLSI 08 International Symposium on VLSI Montpellier FR 2008 pp 463 466 2 H Lebreton ModC lisation de la consommation C lectrique en SystemC TLM et rC duction de la consummation par le contrC4le de mC canisme DVFS DiplC4me de recherche tech nologique Institut National Polytechnique de Grenoble INPG 2009 3 IEEE Std 1666 2005 IEEE Standard SystemC Language Reference Manual NY USA 2006 ISBN 0 7381 4871 7 http standards ieee org getieee 1666 index htmlhttp standards ieee org getieee 4 IEC Std 61691 4 2004 IEEE Std 1364 2001 Behavioural languages Part 4 VerilogB hardware description language 2004 pp 349 374
25. e modules of a timed or loosely timed SystemC platform A further set of functions can also be used for generating various reports of the simulation of an instrumented platform The library works by asking users to re code their monitored SystemC modules such that they also inherit a base class from our library or else set a SystemC attribute for a monitored module to point to an instance of that base classi The Cambridge version release 3 onwards implements energy based logging for transactions and also adds physical dimensions and place and route operations for wire length estimation Energy and power are accumulated in accounts A single account can model both energy and power consumption with energy being the primary representation and power being periodically converted to energy debits Energy figures are converted back to average power in some forms of report Version 3 1 of the library introduces the customer id concept for TLM modelling Energy quanta can now be recorded against a customer activity as well as the olrder approach of recording against a hardware component or subsystem A given quanta can be recorded in both ways giving different views The new approach gives a CPU core or a even a thread process on a CPU core an idea of how much of the system s energy it was responsbile for using Clearly some crosstalk will exist in lower parts of a typical system such as who pays for a cache line eviction which will normally be the ev
26. ectional but off chip connections are some times bi directional using tri state drivers TLM Power 3 0 CBG User Manual 17 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves 3 The wiring energy can be charged to the source or destination component or be separately accounted 4 The cost of bit transition counting is high on most host workstations so de tailed bit toggle counting should be replaced with estimated average values as an user option In a simple example the originator will complete the address field of the payload and for writes also the data and byte enabled fields The intermediate compo nents will forward these fields perhaps with minor changes e g adddress space manipulations at bus bridges or VM units to the destination The destination will reply with a low cost acknowledgment for a write and with the data for a read The PW_TLM_PAYLOAD sub library is provided with the TLM_POWERS library as an extra component for estimating wiring energy when using the OSCI TLM2 0 TLM library It has several modes of operation that are controlled by the prepro cessor variable PW_TLM_PAYLOAD To use the PW_TLM_PAYLOAD LIBRARY the sockets provided by TLM2 0 must be defined with an additional type parameter that extends the generic payload and the socket use sites must be augmented with additional library calls as described below However the user might typically def
27. entation of this function should recompute the en ergy quanta associated with transactions to be logged in subsequent transactions with that supply voltage For example void myram recompute sram pvt parameters Call when Vcc is changed etc 1 Sc time 1 latency sc time 0 21 3 8e 4 sqrt float m bits SC NS pw power 1 leakage pw power 82 0 m bits PW nW m read energy op pw energy 5 0 1 2e 4 8 0 x m bits pw energy unit PW pJ std cout lt lt name lt lt lt lt m bits 8 lt lt byte SRAM leakage power lt lt l_leakage round3sf lt lt Wn set static power 1l leakage m write energy op 2 0 m read energy op rule of thumb m llsc excess energy op m write energy op When using mode phase modelling the values in the underlying table are multi plied by the ratio of the current voltage to their nominal voltage squared before being returned to the user or installed in accounts TLM Power 3 0 CBG User Manual 12 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves 2 12 Logging Power Consumption Mode Phase Approach The mode phase based power consumption approach deals separately with static and dynamic power The mode phase based power consumption is typically used for static power dis sipation It can also be used for dynamic power when per transaction energy is not being used But when dynamic power is being modelle
28. er information to the different computation modes and phases of the FOO module When the power behavior of a model just needs to know the current mode and phase it is possible to use the class PW MODULE This class is an extension of the class PW MODULE BASE As a running example these different facilities were used for modelling the power consumption of a simple platform based on the TLM TAC router 48 As illustrated by the example of Figure 2 the same behavior as the one of Fig ure reffig three can be written more shortly using the class pw module Indeed the associations defined in the configuration file can be used with the method UP DATE POWER for setting the power information TLM Power 3 0 CBG User Manual 13 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves MASTER1 MASTER2 TIMER Figure 2 Simple TAC Platform tac_response tac_multiport_router b_transport tlm_generic_payload amp trans sc_time amp delay 1 unsigned int len trans get data length Main body of the behavioural model Sc time activity time delay lt activity time Or use qk inc to perform this addition ifdef TLM POWERS bit width has been set in the constructor etc Sc energy energy cost pw energy double 5 len pw energy unit PW pJ pw module base update energy energy cost lt activity time endif
29. first waveform of the Figure 7 This waveform shows that the power of the module TOP is equal to the sum of the power con sumed by all its sub components router timer Finally the second call to the function pw_trace generates the second waveform of the Figure 7 which is equal to the power con sumed by a TAC multiport router Note you should put your viewer into analog rendering mode in your waveform viewer for the VCD data generated by this tracer 6 2 VCD Trace Table Output The VCD generator accepts an optional second argument a filename to use for a textual plot file This can be used for gnuplot rendering of the VCD waveforms or for other purposes It has columns of numeric data separated by tab characters with the timestamp as the first field This table can include exactly the same data as in the VCD file but is not in VCD format To plot the global total you need to apply trace to the top of each tree of modules with TLM Power 3 0 CBG User Manual 23 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves sum children mode most designs only have one tree i e they are not forests of SystemC modules A plot_col argument to the trace method allows alters the layout of the plot file entries for that trace as folows Gnuplot expects whitespace separated columns of data and specific columms can be extracted using commands such as gnuplot gt
30. gably to denote an SC MODULE that inherits pw module Currently the two following kinds of report can be generated TLM Power 3 0 CBG User Manual 5 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves 4 CLUSTERO GB module instrumented with power annotations L module without power annotations Figure 1 Example of an Instrumented Platform 1 a time domain plot of the power energy a 2 atable of statistics for power and energy which is written at the end of simu lation but which can be dumped at intermediate points if desired There is also a C API so that user code can read accounting information for generating custom reports 85 The POWERS library supports two basic modelling modes 1 In the mode phase approach the average power consumption of an IP block is set for a period of time as per the POWER 1 library 2 In the energy logging approach quanta of energy are logged into an ac count The two modes can be freely mixed even within a component For instance typi cally we use the mode phase approach for static power consumption and the en ergy logging approach for dynamic and wiring power In the mode phase approach power consumption is determined by the current state of a component A component is free to switch state at any time by invoking library primitives such as set static power There is no protection so a compo nent can ch
31. ictor with our approach The default use of accounts is to use account zero for static power energy and account one for dynamic power energy and account two for wiring power but other accounts can be freely defined For instance for leakage power and for short circuit energy To control account creation please call the start acct method If no accounts have been created before the first logging event the library will create its own default accounts using the following code This latter approach not tested recently TLM Power 3 0 CBG User Manual 4 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves void pw accounting base start default accounts int n t if global n accounts in use gt 0 return start acct STATICO start acct DYNAMIC1 if n gt 2 start acct WIRING2 if n 3 start acct AUX3 A set of accounts is stored in an observer Multiple observers are instantiated for two different reasons 1 itis desired to accumulate data with various subtotal structures 2 different reporting formats of data are wanted The system provides automatically a global observer that sums all energy and power for a simple output but even this is subdivided into the static dynamic and so on accounts An observer may be bf standalone or may include totals for the part of the de sign heirarchy it is the parent to This is controlled by
32. in POWER3 The code from the bus model busmux64 cpp illustrates the two possible styles of energy logging depending on the detail needed Figure 12 10 C Language API We export a C Language API for various uses In the spEEDO project in Cambridge we are exploring power aware schedulling One mechanism we provide is for a processor core to read off system wide and local energy consumption On the real board the processesor TLM Power 3 0 CBG User Manual 27 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves reads from physical supply measurements and in the TLM model of the same system the processor reads values captured from the POWERS library The main call to use is to apply pw_stat_observer_base pw_get_observer sc_object on part of the design heirarchy This returns a handle on that part 11 Implementation Notes The TLM Power library is fully compliant with the IEEE 1666 standard and has no depen dencies other than the SystemC library itself It can be used as a static standalone library or as an ST INFRA development kit To use it an application shall include either of the following C headers 1 tim power this header adds the names sc pvr to the declarative region in which it is declared It also adds in this namespace all the components requested for using the TLM Power library 2 tlm power h this header adds all of the names from the namespace s
33. ine their own CPP macros that inte grate the TLM 2 0 socket operations with the PW_TLM_PAYLOAD library calls The third generic argument to socket definitions must be provided and defined as PW_TLM_TYPES The signatures to the transaction methods also need to be defined to use PW_TLM_PAYTYPE instead of the standard generic payload These two changes have no effect when PW_TLM_PAYLOAD is set to zero since the macros are then defined as their defaults but for other values the extended generic payload is used Providing the third template argument to a socket tlm utils simple initiator socket tracedriven core btlm 64 PW TLM TYPES initiator sodket Using the extended generic payload in the transaction methods void b access PW TLM PAYTYPE amp trans sc time amp delay The three primitives used for bus energy modelling are pw set origin pw terminus and pw log hop calls These mark the beginning intermediate steps and end of a TLM payload trajectory void pw set origin sc module where uint flags 0 bit transition tracker transition reference 0 pw_handle pw log hop sc module where uint flags 0 bit transition tracker transition reference 0 void pw terminus sc module where The first argument where is the this pointer for the current component This is used to track the path through the system The second argument is the flags Most flags are sticky and apply to subsequent hops that do n
34. n overflow is detected the resulting value is equal to the maximal power value when an underflow is detected the resulting value is equal to zero when a division by zero is detected the resulting value is equal to the maximal power value TLM Power 3 0 CBG User Manual 8 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves 2 4 Physical unit Energy in Joules Much like the pw_power class the class pw_energy is used to represent electri cal energy values and has the same functions The default energy resolution is 1 pico joule and the physical unit is also represented by an enumerated type pw_energy_unit i e pw fJ for femto joule pw_pJ for pico joule pw JOULE for Joule 2 5 Physical unit Length in Metres Much like the pw_energy class the class pw_length is used to represent physical length and has the same functions The default energy resolution is 1 pico metre SHOULD BE micron by default and the physical unit is also represented by an enumerated type pw energy unit i e pw_fm for femto metre pw pm for pico metre pw METRE for metre 2 6 Physical unit Area in Metres Much like the pw length class the class pw area is used to represent layout area and has the same functions The default area resolution is the square micron and the physical unit is also represented by an enumerated type pw area unit i e pw_squm for square microns pw_sqcm for square ce
35. names Any component sc module can be specified as having a separate chip name Its area and power are not included in that of its parent component TLM Power 3 0 CBG User Manual 16 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves Moreover the inter chip wiring model is applied to transactions and nets that cross between chips Placement and hence wiring distance can be determined in two ways e Geometric Placement With geometric placement every component is al located 2 D co ordinates inside the perimeter of its parent Geometric place ment is based on heuristic algorithms based on random numbers It can give unpredictable results and users should interpret results only after making several runs with different random seeds Rentian Placement With Rentian placement no actual placement co ordinates are determined and no random number generation is required Instead wiring distances are given according to Rent s Rule based on component area The lowest common module that contains the two ends of an intercon nect is found by walking up the module hierarchy until a common SC MODULE is encountered The wiring distance is then predicted from the area of that module Placement Every component is allocated 2 D co ordinates inside the perimeter of its parent Rather than performing an accurate placement based on geometric tessellations each component is assumed to be a
36. nent and also its children for the summing variant The observer API should be used for reading energy use How to get a handle on an observer for the current SC MODULE Sc pwr pw stat observer base it pw get observer this Sc pur no children How to get a handle on an observer for the current SC MODULE and its children Sc pwr pw stat observer base it pw get observer this Sc pwr sum children How to get a handle on a global summing observer for the complete system Sc pwr pw stat observer base it pw_get_observer 0 Sc pwr sum children sc start At any point then we can print as follows std cout lt lt Energy in account lt lt it gt get global name 0 lt lt is lt lt it get energy 0 lt lt Wn std cout lt lt Energy in all accounts lt lt it gt get_energy lt lt Wn 6 Tracing Facilities Three different forms of trace report can be generated with the TLM POWERS library These include SyLK VCD and TEXT All three include power and energy consumption utilisation Transaction tracing is now being added The library will automatically add up the power and energy used globally but the top module must be traced using one of the trace methods to see this global total in the associated trace file Individual sub systems may also be traced by selecting other points in the hierarchy to trace and passing the associated component as an argument to
37. ns pw_terminus this Figure 4 Energy based instrumentation of TLM call inter module component logged The second argument is either SC_TIME_ZERO if utilisation logging is not required or appropriate or else the time for which the component has been active since the last call to update_energy Using loosely timed models the activity time is either the time accumulated in the current component or the time accumulated between call and return from the transport method according to whatever definition of utilisation is required The observers currently add the energy part to the dynamic energy aggregate and time part to utilization aggregate Thus at any instant utilization simulated time gives the percentage of time that a module has been busy In the future one could record utilization per quantum to observe busy periods for a module so as to spread its work load over time or over number of modules if needed In the TLM POWERS library the energy is scaled by the standing supply voltage squared unless the optional noscale true parameter is passed to update_energy Figure 34 illustrates a basic form of the companion approach where transactional energy consumption consumed in wiring is logged This is the inter module energy See 8 refsec tlmwiringenergy for full details 2 14 Logging Length and Area A component can describe its physical size in its constructor using one of the following TLM POWERG calls Set a
38. ntimeters pw sqmn for square millimetres and pw_sqm for square metres 2 7 Physical unit Voltage in Volts Much like the pw energy class the class pw voltage is used to represent poten tial difference values and has the same functions The default energy resolution is 1 pico volt should be VOLTs and the physical unit is also represented by an enumerated type pw energy unit i e pw V for femto volt pw pV for pico volt pw VOLT for volt TODO THESE UNITS SHOULD ALL BE FULLY DOCUMENTED IN TABLES Finally some arithmetic operators using these various classes plus the SC TIME class are provided for performing multiplication and division with different physical quantity parameters TLM Power 3 0 CBG User Manual 9 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves 2 8 Instrumenting a SystemC module Approach 1 inheriting the pw_module class FOO public sc_module public pw_module public SC HAS PROCESS FOO FOO const sc module name amp p name int width sc module p name pw_module config txt F Approach 2 having a reference to a power base details missing Class pw module base should be listed as a base class of a SystemC module that is instrumented for power monitoring The SystemC module should also inherit Sc module as usual The constructor for a module such as a RAM or CPU is typically provided with
39. o the constructor and this again may be based on the SystemC kind O or on the Sys temC instance name name Generally the latter is not needed since each in stance should be identically parameterised in terms of technology constants even if different in per instance parameters such as size TLM Power 3 0 CBG User Manual 10 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves An XML version of the file may be supported in the future The entries in the file have the following purposes e Mode Line Defines a dynamic power mode and phase Voltage Line Gives the supply voltage for which the powers in the mode line are correct Variation w r t supply squared is assumed If this line is omitted a one volt supply is assumed Size Line Gives the physical dimensions of a module a width and length pair Generally there is no difference between width and length and they are mostly just multiplied to give the module area Location Line Gives the X Y coordinates of a module if detailed placement is being used currently unimplemented the lowest common parent approach is used instead The syntax of a configuration file respects the following pseudo EBNF grammar line i MODELINE VOLTAGELINE SIZELINE comment VOLTAGELINE i v voltage SIZELINE s length length MODELINE DE m MODE PHASE DYNAMIC STATIC MODE string PHASE string DYNAMIC power STATIC oS po
40. onsumption Waveform more delta cycles have elapsed since opening the file A VCD trace file shall be closed by calling the close method of the trace object at the end of the simulation There are two styles of VCD plotting for energy events averaging and decaying For the decaying form of tracing new energy log events are upwards impulses that then decay The VCD tracer accumulates new energy while geometrically writing off the old energy For the averaging form of tracing we render energy events as rectangles with area proportional to energy use Their height is the average value in that interval The rectangle for an energy quanta could possibly best be centred around its log event but we draw the rectangle ending at the log event In both styles phase mode changes are rendered as rectangles whose duration corresponds to the interval in that phase mode The decaying plot again represents energy as area This is computed by scaling the initial height of the energy impulse inversely with the decay rate The time constant for the decay is set as XXX Figure 7 shows the waveform diagram of the VCD trace file generating by the simulation of a modified simple TAC platform This uses phase mode annotations only As illustrated by the code of Figure 10 the main method was modified to create the trace file and indicate the modules to monitor TODO Can t we capture them all by default The first call to the function pw trace generates the
41. ot change that flag In particular if the flags argument is zero for the next hop then nothing has changed and the next hop has the same properties as the previous hop TLM Power 3 0 CBG User Manual 18 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves Name Description Notes PW_TGP_ADDRESS The address field contains Sticky amp live data PW_TGP_DATA The data field contains Sticky amp live data PW_TGP_LANES The Sticky amp byte lanes contain live data PW TGP MUXD AD The address and data fields contain Sticky amp live data which are sent over a common bus PW TGP NOFIELDS No fields contain live data Sticky amp apart from command response Table 1 Active payload field PW TGP XXX Name Description Notes PW TGP ONCHIP The next hop uses the on chip Sticky amp wiring costs PW TGP OFFCHIP The next hop uses the off chip Sticky amp wiring costs Table 2 Bus energy model PW TGP XXX The third argument is a bus reference Every transaction is considered to take place over a bus and a bus is a generic set of wires modelled with a bit transition tracker Wires present that are not used consume no energy so it is not important to cus tomise the instance of a bus to its use e g the bus from CPU to memory has address and write data whereas the return bus has just read data The bus
42. plot plot dat using 1 2 title DRAM plot dat using 1 3 title CPU typedef enum DoNotPlot PlotEachAccount PlotCombinedAccounts plot_control_t 6 3 VCD Plot Future Improvements The VCD plot legends contain the word energy but the plot is power Perhaps the same plot control t should be supported for the VCD output itself Then all accounts within an observer can be summed and shown as one line on the VCD graph 6 4 Textual Statistics File A text file gathering different statistics about power consumption can be created and opened by calling function pw create txt trace file lt may be opened during elaboration or at any time during simulation The modules to monitor are defined by calling function pw trace A textual file shall be opened before the power changes of the monitored modules and shall be closed by calling the close method of the trace object at the end of the simulation As for the VCD trace file the code of the main method was modified for generating a textual file and indicating the modules to monitor The first part of this file Figure contains the elapsed simulation time used for computing the different power statistics and the three following arrays e The first array contains the dynamic and static energy in Joules consumed by the monitored modules The percentage values indicate the dynamic or static energy consumed of a module compared to its global consumption e The second array contain
43. refer ence is needed so as to check which physical nets are transitioning with respect to their previous value 3 3 TLM Wiring Energy Modelling Computation The formula used for energy consumption is a straightforward product of three numbers 1 the length of the current hop in millimetres from Rentian or other wiring estimator 2 the number of bits that have transitioned measured or estimated 3 the energy per millimetre per transition for the wiring style being used taken from technology file 3 4 TLM Wiring Energy Modelling Flags The flags field is a bitwise OR of one or more of the PW TGP XXX flags Cer tain flags are mutually exclusive with only one from each group being allowed TLM Power 3 0 CBG User Manual 19 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves Name Description Notes PW_TGP_SRC_ACCT The energy for the next hop s Sticky should be debited to the current component PW TGP DEST ACCT The unaccounted wiring energy Sticky so far should be passed on to a subsequent component PW TGP CKP ACCT The unaccounted wiring energy Non sticky so far should consolidated to the current or originating component depending on the pertaining sticky in methods Table 3 Bus energy accounting methods PW TGP XXX 3 5 Transition Density Estimations Rather than measuring the bit hamming distances on every operation which i
44. s expensive the library uses a so called jb confidence switcherj b This is a template that fully executes a function some first number of times N 1000 or so but after that the average of these first calls is returned instead This greatly saves execution time for the function Two refinements are applied to this basic approach 1 To avoid warm up effects the average of first N calls is disregarded and the second N worth of calls is used for calls 2N onwards 2 To check for non stationary behaviour after 2N calls the underlying function is called once in every N applications and the result compared with the average If it is out of kilter a warning is printed Ed please be more precise here 3 6 TLM Wiring Energy Modelling Example Blocking Style We will first explain its use with the blocking TLM coding style assuming that the TLM is forwarded through one or more passthough sockets in the NoC or bus model to an endpoint e g a RAM and returned the same route Here is the basic code for an annotated initiator Note that different fields in the bus are active depending on whether it is a read or a write transaction Example code for a blocking TLM initiator if R trans set read else trans set write trans pw set origin this PW TGP ADDRESS PW_TGP_ACCT_SRC CR 0 PW TGP DATA PW TGP LANES amp forward bus initiator socket b transport trans delay trans pw terminus this The forwar
45. s the same information as the one before but for power consumption in Watts e The third array gives the power contribution in percentage of the monitored modules The second part of the generated textual file details the power consumption of each module For example Figure illustrates the power information given of the first memory bank As before this section is composed of three arrays where the column module is replaced by the power modes e g ON and phases e g IDLE READ used by this memory during the simulation 6 5 SYLK Statistic File As for the textual trace file the SYLK Symbolic LinK trace file gathers different statistics about power consumption The functions for managing this format of trace file is the same as the ones for the textual trace file except their suffix names TXT_TRACE_FILE is replaced by SLK TRACE FILE The main advantage of this trace file format is to be supported by most of the spreadsheets TLM Power 3 0 CBG User Manual 24 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves E Microsoft Excel power trace result slk 5 x Bi Fichier Edition Affichage Insertion Format Outils Donn es Fen tre Tapez une 8X Qj idiciaaTZxsums y c m9r iiuueoo Bw 10 e z sj B m 3 sE i 6 A B AT bd f MODULE NAME B C D E G 1 MODULE NAME DYNAMIC ENERGY
46. tatic pwr get static power ON ROUTE set power mode PW MODE ON set power phase PW PHASE ROUTE set dynamic power get dynamic power 1 dynamic pwr set static power l static pwr endif existing TAC code ifdef TLM_POWER if 1_nb_transaction 1 this gt update_power ON IDLE else set dynamic power get dynamic power 1_dynamic_pwr l nb transaction endif Remainder of behavioural model output port do transport router request response TLM CALL Figure 11 Mode Phase TLM Power 2 Style instrumentation of the TAC Multiport Router if PW TLM PAYLOAD gt O POWER3 1 agent record energy use std energy op POWER3 trans pw log hop this Second call after return else POWER3 record energy use std energy op endif Figure 12 Energy quanta logging in b transport method for dynamic and wiring energy Static power still typically uses phase mode style for modelling the power cost of routing a transaction This example also illustrates how to use the methods of the classes pv module base and pw module for modelling a complex behavior using a configuration file The code of this platform is delivered with the library and can be compiled as is i e no external dependency other than SystemC 9 Modelling Example Energy Logging The nominal processor example in the tests folder is an example of the preferred energy quanta logging coding style This is new
47. the file physical txt The user can change the name of this file by assigning his own string to this global const char sc pwr phy report name physical txt 2 11 Voltage Scaling Each component has an associated supply voltage A component can adjust its local supply voltage using either of the following two calls void set vcc const pw voltage amp bool update children true void set vcc double pw voltage unit bool update children true By default these will update the supply voltage to all child components on the same chip or region Note that this will not be the complete chip region if this call is not made at the top level component of that chip or region Energy consumption is typically proportional to supply voltage squared Perform ing a floating point multiplication for every energy logging operation is expensive and so the energy quanta are typically held pre scaled in the users component model and recomputed only when the supply voltage or other PVT component changes To facilitate this in the user s constructor the device should first set its supply volt age if it wishes or else use the voltage inherited from its parent Then it should call a locally defined function called recompte pvt parameters which is a locally supplied override to a virtual function defined in sc pwr pw module base The POWERS library will call this function whenever there is a supply voltage or other PVT change The user s implem
48. tialised with a unique internal identifier by its constructor in the library A coupled observer is also created It must be associated with a SystemC module for callback reasons but it has no further association with that component It has a user name and optional index for presentation purposes The customer identifier can be passed in to the record energy use main logging API for energy to be credited under the account The customer identifier can be carried arround easily in our version of the generic payload provided this is enabled in the macro setting TLM Power 3 0 CBG User Manual 7 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves Put a customer number in a transaction PW_TLM_PAYTYPE trans trans set customer acct customer id At various places use the following to record energy not only against the local structural observers but also against the customer noted in the payload record energy use op energy amp trans When customer identifiers are in use and a call to record energy use is made without a customer identifier being given the energy is logged to the local struc tural accounts AND to a special customer account provided by the library called anonymous The grand total figure is unaffected whatever is logged is recorded in this exactly once always 2 2 Physical Data Types As in the SystemC SC TIME class the TLM Power libr
49. tion Density Estimations oss ss so ss a 3 6 TLM Wiring Energy Modelling Example Blocking Style 3 7 TLM Wiring Energy Modelling Example Non Blocking Style 3 8 Non TLM Wiring Energy Modelling Example A Physical Reports oa C API Tracing Facilities 6 1 VCD Traces 62 VCD Trace Table Output lll 6 3 VCD Plot Future Improvements 004 6 4 Textual Statistics Filel ole 6 5 SYLK Statistic File Options 7 1 Net Transitions 7 2 DMI Callbacks 90 O 0 C Language API 11 Implementation Notes 11 1 Compilation Modes TLM Power 3 0 CBG User Manual Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f Modelling Example TAC Simple Basic Platform Modelling Example Energy Logging 16 16 17 19 19 20 20 21 21 21 21 22 22 23 24 24 24 25 25 26 26 27 27 28 28 MY Yasin C Koch Hofer Pascal Vivet DJ Greaves 1 1 1 12 Messages 29 12 1 Warning Messages llle 29 12 2 ErmorMessages lll 31 Introduction Accounts The TLM Power 3 1 library is a framework for logging power consumption for Sys temC 3 models with emphasis on TLM transaction level modelling It can also help with area and component utilisation modelling This library defines a set of classes and functions for evaluating the power consumption of th
50. turn_bus Example code for a blocking TLM end point that is to return a payload cmd tlm TLM READ COMMAND PW TGP DATA PW_TGP_NOFIELDS PW_TGP_ACCT_CKP 3 7 TLM Wiring Energy Modelling Example Non Blocking Style This text is missing TODO 3 8 Non TLM Wiring Energy Modelling Example Energy use in individual net transitions that are not part of a TLM payload or which use non standard TLM interfaces can be logged as follows This text is missing TODO 4 Physical Reports Physical report files may be written by the library including area and layout A generated file default name physical txt describes the module hierarchy by voltage scaling domain and gives area at each level 5 C API Each annotated component type sc module has a power module of type pw module base as a base The basic form of C API is provided through the methods of this base class This contains static information about component size and varying information such as the current mode phase power for each account At any point we can read off the total energy used so far TLM Power 3 0 CBG User Manual Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f 21 MY Yasin C Koch Hofer Pascal Vivet DJ Greaves const sc_pwr pw_energy 1 global energy pw stat observer base get global energyO However each component has a summing or standalone or both observers which provide cummulative data for that compo
51. wer string a zA Z voltage ss floating literal VOLTAGEUNIT length i floating literal LENGTHUNIT power floating literal POWERUNIT VOLTAGEUNIT fV pV NV uV mV V LENGTHUNIT z 2 nm um mm cm m POWERUNIT fW pW nW uW mW W A limitation of the parser currently used is to not support spaces between the floating literal and the unit token of the power rule 2 10 Chip Region Name Every component is nominally on a given chip which has a textual name It is sometimes convenient to use this mechanism on a finer grain and hence the name is sometimes a region name rather than a chip name A component is sometimes conveniently allocated a chip region name as an op tional parameter to the area setting calls Otherwise the specific set chip region std string amp method should be called in the current region Either approach will recursively set the chip region for the child objects that are unset All regions or chips that are supposed to be different must be given different names by the user TLM Power 3 0 CBG User Manual 11 Version CBG 3 2 Alpha DRAFT MANUAL UPDATED 1Q2015 Rev f MY Yasin C Koch Hofer Pascal Vivet DJ Greaves These calls also enable the chip region of the current component to be given If no name is given then the name of the instantiating parent is used At the top level if no name is give then the SystemC name is used Chip names and other layout details are reported in

MY Yasin, C Koch-Hofer, Pascal Vivet, DJ Greaves . TLM Power 3.0

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