(System Co-Simulation and Performance Estimation) User Manual
Contents
1. DS2 and University of Cantabria UC 4 INSTALLATION Before you can use SCoPE you must have some software installed 4 1 Software Requirements e GNU C C compiler gt 4 0 e SystemC 2 2 4 2 Environment variables Edit your bash_profile or bashrc file and add the next environment variables e CXX g e SCOPE_HOME path to scope e SYSTEMC path to systemc Additionally it is recommended to add the SCOPE_HOME bin folder to your PATH Otherwise the complete path to scope g compiler will be required each time a SW task is Example bashrc export SYSTEMC home SystemC systemc 2 2 0 export SCOPE_HOME home SCoPE SCoPE 1 1 5 export PATH PATH SCOPE_HOME bin 4 3 Internet resources Once you have reached this point you can get SCoPE and proceed with its installation To download it you should go to e Download http www teisa unican es scope Once there download SCoPE 1 1 5 version July 2010 Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC 4 4 Installation rules For the tool compilation once set the previous environment variables it is only required to execute the make command Command Explanation make Prints the Makefile help make all Compiles SCoPE sources make test Compiles all tests Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC 5 CREATING A SCoPE SIMULATION In order2. SW object files the HW files the SCoPE library and the SystemC library to create the executable Remember to compile the sc_main file including the SCoPE and SystemC headers This file is compiled using g not scope g Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC 6 Application software running in SCoPE If you want to run your software application in SCoPE you have to be careful in some aspects 6 1 Restrictions of SCoPE to the application SW SCoPE restrictions are mainly due to problems of implementing the internal parser although there are some other o Use of SCoPE protected names SCoPE uses some variables and functions for its internal operations Their names can not be redefined in the application SW to avoid name collisions All SCoPE names start with uc_ so it is highly recommended not to include in the application sw any name starting with that prefix o Application Programming Interface API Nowadays only two APIs are implemented which are POSIX and UCOS If the embedded software application is made on another interface will not work m POSIX POSIX SCoPE s API was the first API implemented The functions are the same but adding the prefix uc_ For example to create a task it will be uc_pthread_create instead of pthread_create The parser is responsible for redirecting the original API calls to the API SCoPE calls The prefix is automatically added b
3. 0 5 3 1 Creating the SW infrastructure To create the SW infrastructure it is required to instantiate as OS models as required For each model it is required to indicate the number of processors that will be controlled by the OS Remember that the OS models are SMP systems so they can control several processors at the same time The creation of the OS models can be done with the following line UC_rtos_class rtos new UC_rtos_class num processors If it is required to load any device driver a call to insmod will be required insmod rtos driver_init_function Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC 5 3 2 Loading the application SW To load the application SW it is required to load in the OS models the name of the entry function of each application in the following way rtos 0 gt new_process int int char function void arguments rtos 0 indicate the processor where the task should start However as the OS model is SMP the OS can decide to move the task to any free processor when required to balance the system load To define the processors where a task can cannot be moved the sched_setaffinity function can be called in the application SW code not in the sc_main 5 3 3 Creating the HW platform description To create the platform the HW components must be created and connected The following example create a node with a bus a memory
4. and a network interface Creating the bus UC_TLM_bus_class bus new UC_TLM_bus_class sc_gen_unique_name HAL freq Processor binding rtos 0 gt bind bus repeat for all the cpus rtos 0 rtos 1 rtos 2 Creating and connecting the memory UC_hw_memory mem new UC_hw_memory sc_gen_unique_name mem RAM_START RAM_START RAM SIZE 1 100 resp time ns bus gt bind mem Creating and connecting a network interface UC_hw_Noc ethil new UC_hw_NoC sc_gen_unique_name eth NET_START NET_START Ox3F NET_IRO irg 10 delay noc simulator bus gt bind ethl Finally it is required to indicate the address of the main memory and create the memory map The memory map is created with the address of all the components connected and it will be used to deliver all the incoming transfers to the appropriate HW peripherals bus gt set_memory_address RAM_START bus gt generate_memory_map To include a network the following steps must be followed UC_NoC_Interface noc_simulator new UC_NoC_Interface simulator 1 false int addrs x_size y_size z_size numbers 0 0 0 ethi gt get_node numbers 1 0 0 eth2 gt get_node noc_simulator gt set_structure int addrs x_size y_size z_size 5 3 4 Creating the executable Once accomplished the previous steps the simulation executabe can be obtained by linking the sc_main object file
5. for SW execution modeling SCoPE provides a simulation technique alternative to instruction set simulators ISS obtaining speed ups in factors about x100 in exchange of performance estimation errors of about 10 To do so SCoPE applies the latest techniques on annotated native co simulation with high level TLM HW platform models SCoPE is a tool specially oriented to the fist steps of development in the design process I fact it is a good technical solution for two main purposes Explore the best system configurations SCoPE allows fast modeling of your SW and HW components in a complete platform model Thus you can analyze the performance results of your possible configurations exploring the effects of different components such as processors or the effects of different architectures SCoPE provides facilities for automatic system exploration e Put at disposal of your SW designers a virtual platform where the interaction with HW components and in general the effects of the planned system can be considered Thus the development of the SW can start without requiring a HW prototype reducing the time to market of your products Additionally as the native simulation speed is close to the obtained running the SW in your PC SW development time is highly reduced compared with current ISS based simulation techniques From a technical point of view SCoPE is a SystemC extension for system modeling based on approximately loosely timed descrip
6. to create a SCoPE simulation the designer must follow the next steps Compile the application SW using scope g tool instead of the standard gcc g Compile the user defined HW components using g not scope g Generate and compile a sc_main cpp file including the sc_main function with the system description Link the sc_main SW object files the HW files the SCoPE library and the SystemC library to create the executable 5 1 Compiling the application SW To compile the application SW it is only required to execute the same gcc g instructions used to generate the object files in the host computer but replacing gcc g by scope g Make sure the command contains the gcc flag c in order to generate object files o instead of an executable Additionaly it is required to add to the compilation command e scope cpu cpu_to_use e g arm926t IS SCOPE_HOME include IS SCOPE_HOME scope If the main functions of the application SW are called main it is recommended to change the name manually Otherwise scope g will replace them by uc_main The main function is SystemC is implemented inside the SystemC library If several applications will be simulated this modification is mandatory in order to identify each application in the sc_main file 5 2 Create and Compile the user defined HW SCoPE HW components are interconnected using the standard TLM2 interfaces Thus any HW model de
7. 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC 8 Glossary Application Programing Interface API Set of routines data structures object classes and or protocols provided by libraries and or operating system services in order to support the building of applications Approximately timed Modeling style for which there exists a one to one mapping between th xternally observable states of the model and the states of some corresponding detailed reference model such that the mapping preserves the sequence of state transitions but not their precise timing Computing group Group of computing elements usually processors organized to work cooperatively emulating a more powerful single computing unit The elements of the computing group work controlled by a single operating simple and usually in a symmetric way Design Space Exploration DSE Process that explores all the system design possibilities in order to obtain an optimal design Extensible Markup Language XML General purpose specification for creating custom markup languages It is classified as an extensible language because it allows the user to define the mark up elements XML s purpose is to aid information systems in sharing structured data especially via the Internet to encode documents and to serialize data HW platform Group of HW components working together that provides the required support to the SW
8. July 2010 SCoPE System Co Simulation and Performance Estimation User Manual Version 1 1 5 Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC Copyright Notice Copyright c 2007 2010 by Design of Systems on Silicon DS2 and the University of Cantabria UC All Rights reserved This software and documentation are furnished under dual GPL and LGPL license The software and documentation may be used or copied only in accordance with the terms of the license agreement Right to Copy Documentation The license agreement permits licensee to make copies of the documentation Each copy shall include all copyrights trademarks service marks and proprietary rights notices if any Disclaimer THE CONTRIBUTORS AND THEIR LICENSORS MAKE NO WARRANTY OF ANY KIND WITH REGARD TO THIS MATERIAL INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE Bugs and Suggestions Please report bugs and suggestions about this document to http www teisa unican es scope Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC The SCoPE infrastructure has been created by the following individuals Main developer H ctor Posadas Assistant developers Juan Castillo David Quijano Additional contributors Luis Diaz Sara Real Daniel Calvo Pablo Gonzalez Patricia Botella Gerardo Caballero This docum
9. To modeling the application SW the source code is first annotated adding performance information and then natively executed together with the rest of the simulation GES Figure 1 Structure of a complete SCoPE system model The SW infrastructure is composed of a OS model which is in charge of providing concurrency scheduling communication and timing services to the application SW To do so a POSIX API is provided Additionally HW SW support based on the Linux functions for device drivers are included in the model Finally generic models for several common components such as buses memories network interfaces or DMAs are provided using SystemC TLM2 standard interfaces Combining these components and adding user defined HW components a wide range of platform architectures can be modeled Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC In order to create the system model indicating the HW and SW components and their interconnection a sc_main function following the SystemC rules is required from the user Its creation will be explained the the following chapter This file can be avoided providing all this information in XML format through the M3P or the IP XACT plug ins 3 1 Application SW performance annotation For modeling the application SW performance the source code is analyzed in order to estimate the time and number of instructions of each code basic block This informatio
10. W cccccssscesseceseeeseeceeeeseeceeeeseeceaeeeseeeeeeeeeeeaeeeees 18 5 3 Generating the sc_main MINCT OMe vesexcs eres ee scteuscavsc eceecdssaatesdevedevauccevacaYonetnetsteadsiese Aas nti eases 19 5 3 1 Creating the SW inffastriCture 2 cs0icsosaivedecasideaiesasccuwssuyedecouabecducessduseosasecessatysdatcnsececcssbue 19 5 3 2 Loading the application SW seesessesesseserssressessrsseessesersseesessesseesresseeseeseesseeseessessseeese 20 5 3 3 Creating the HW platform Cescription cccsscssscccersessscsescesscesssssseccsnscetsceessencesens 20 5 3 4 Creating the execittable si cs cccscscdscassastesneicosshesansastusscssvteessntsancdsenvhuteansevestcosteesseeceneentenese 20 6 Application software running in SCOPE cssccsscsssssssscessccesscecsnssnscesaccesscssansessnceesesseeesesensecs 21 6 1 Restrictions of SCoPE to the application SW ccccesceesceceseceseeeeeeeeseeeseeceeeeseeeeeeeeeeees 21 6 2 General restriction on the code for the native simulation ssssesesseeseeeseesssressseressseresse 21 PUGS AMG suggestions ess ued uke Lane E Aa AE TE TE OS ENE eE ESE 22 NGOS SAI Yo E ie ug tu Die ea E R EE NER E A E O R Moc Acne AUR 23 Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC 1 OVERVIEW SCoPE is a simulation infrastructure oriented to fast simulation of MPSoC HW SW systems It combines easy creation of platform models with fast techniques
11. W modeling mechanisms scope verbose show the internal operations scope preserve files preserve the annotated files Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC scope language c c indicates if the file to be compiled is c or c to call the gcc or g native compiler Otherwise the file extension is used SCoPE compiler at disposal in the basic distribution performs 3 types of operations Modify the OS function calls to access the OS model instead of the host OS annotate execution times and annotate instruction cache accesses There are additional flags to select which operations must be done scope notime disable the time annotation scope noicache disable the instruction cache annotation Other flags can be used when using the SCoPE plug ins Its usage can be shown in the corresponding plug in user guides SCoPE annotation is made in a way that is hidden during debugging steps Thus SW development using gdb or other c c debuggers is possible 3 2 RTOS Modeling This library models the detailed behavior of the RTOS including concurrency among tasks in the same processor parallelism among tasks in different processors scheduling and synchronization Although the SystemC kernel executes processes following a non preemptive scheduling policy without priorities SCoPE models preemption under different scheduling policies based on priorities 3 2 1 Operating syste
12. anced vets a E ER E S on 11 Be oCOPE modeling capabilities mniersreeiireciinni nnr endase eiie terie erasi tE 12 3 1 Application SW performance anmotatiOn cccccescecesecesceeeseceeecesecescecsseceseeeeeeceeeessesesaeeees 13 3I Z RTOS Modeling zp eiie eaaa ie E aE Se ESE aati eG retta heats 14 3 2 1 Operating system interfaces ssseseeeseesseeseesorssteseesorsseesoersrssersoessesserssessessoesseseesssereseo 14 3 2 2 Deyi Drivers 5 siesateenssing bats castast ons aateaateluae das a a E a E EE E lamas 14 Seo HW Platform modeling nisn ressn anan a e a a a E Eaa 15 3 3 1 Hardware platform simulation seseeseeeseeseesseeseesressreseeseessresetsseeseeserssreesseeesseeressseeesse 15 3 3 2 System SUMMATION shee r an aeara Eee NE EEEE Ra EEVEE EENAA E E AARE EELEE FES 15 A INSTA LECA EL CUING mienge yada vege ee vase vans dune aaa a a bas ah Gov ais aA ava aM 16 4 1 Software RK CQUITEINCIS 00sec outa onli tei lege ncdid oc hd ates date AT Geahed Neuse leateiee Wreedadndesees 16 4 2 Environment variables 52 esexcsistasdeee toateves e E E a a dee aieea 16 Ao lnternet resources n a vas vaste ne aV N EEA OEL A E A a E E AES 16 4A Installation r leS inian A E Aa AEAEE EER 17 5 CREATING A SCoPE SIMULATION eeseeesesesseseseseestsesseesrsesretstsestsestrsesrseesesesteseseseeseseserens 18 5 1 Compiling the application S W shut ata dice fhe Riedie ven eee Lye See Nach Stance whos 18 5 2 Create and Compile the user defined H
13. astructure SCoPE simulation infrastructure provides a complete set of facilities for fast modeling of complex embedded systems SCoPE allows modeling from simple systems composed of a processor a bus and a memory to MpSoC with NoC systems Designers can use that simulations for functional purposes developing and checking the correct behavior of the system components or for performance evaluation obtaining information about delays resource use power consumption cache efficiency bus or network traffic temperature increase etc The open source components of SCoPE are SCoPE simulation core M3 Plugin for Design Space Exploration The non open source components that can be added to extend the basic SCoPE facilities are the following Optimized SW estimation plug in Cache modeling plug in including optimized instruction caches data caches and L2 caches IP XACT platform description plug in Win32 API plug in Thermal floor plan analysis plug in Sicosys network modeling plug in TCP IP plug in Real Time Linux plug in 2 1 Open source components 2 1 1 SCoPE simulation core The SCoPE simulation core or in general SCoPE contains the basic simulation infrastructure and it is required for all the other components to work It is delivered in open source format under GPL and LGPL licenses The main features are the following SW modeling o Approximate estimation and modeling of SW simulation times o Approximate instruction cache mo
14. ch described by ordinary C syntax Instantiated in the SystemC framework the objects described in this manner may communicate in a simulated real tim nvironment using signals of all the datatypes offered by C some additional ones offered by the SystemC library as well as user defined SCoPE SystemC framework for system modeling based on approximately loosely timed descriptions of the system components Timed simulation Simulation performed using timed models of the system components The resulting simulation considers both the system functionality and the associated timing Transaction Level Modeling TLM High level approach to modeling digital systems where details of communication among modules are separated from the details of the implementation of functional units or of the communication architecture Transaction requests take place by calling interface functions of these channel models which encapsulate low level details of the information exchange Communication mechanisms are modeled using channels such as busses or FIFOs TLM2 The second major version of the OSCI Transaction Level Modeling standard Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC
15. chnology for estimating time and power of SW components This plug in offers a more accurate and simple estimation technique even considering cross compiler details and optimizations 2 2 2 Cache modeling plug in SCoPE basic package provides an initial technique for instruction cache modeling but no data cache or L2 cache modeling is possible This plug in provides a complete modeling solution obtaining much more accurate results with a minimal simulation overhead 2 2 3 IP XACT platform description plug in This plugin allows describing the HW platform using IP XACT descriptions instead of SystemC codes Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC 2 2 4 Win32 API plug in The plug in provides an additional API extending the operating system model provided with SCoPE This plug in models a win32 api 2 2 5 Thermal floor plan analysis plug in Considering SCoPE power estimations the designer can define different floor plans for the implementation of the system under development and evaluate the resulting temperature values for the running SW 2 2 6 Sicosys network modeling plug in SICOSYS is a general purpose interconnection network simulator for multi procesor systems that allows the modeling a wide variety of message routers in a precise way Results are very close to those obtained by using hardware simulators but at lower computational cost It is provided by the University of Can
16. components and provided the required specific functionality required to perform the required application s HW SW partition Process of dividing the system functionality in SW and HW components Instruction Set Simulator ISS Simulation model usually coded in a high level programming language which mimics the behavior of a mainframe or microprocessor by reading binary instructions and maintaining internal variables which represent the processor s registers Metric Set of units which can be used to specify anything which can be measured along with the procedures to carry out measurements and the procedures for the interpretation of the assessment in the light of previous or comparable assessments Metric Definition file XML file listing the system metrics the simulation must measure and report Network on Chip NoC Is a new approach to System on a chip SoC design NoC based systems can accommodate multiple asynchronous clocking that many of today s complex SoC designs use The NoC solution brings a networking method to on chip communication and brings notable improvements over conventional bus systems Node Active electronic device or group of devices attached to a network and capable of sending receiving or forwarding information over a communications channel A node is a connection point either a redistribution point ora communication endpoint Platform Sort of hardware architecture or softwa
17. deling Operating system modeling o SMP Operating system core model based on the POSIX standard o POSIX api o uCos2 api o HAL infrastructure following the Linux functions for character devices Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC Network driver for the generic HW network interface HW components o Generic HW component models for bus memory dma mesh network and network interface An engineer using SCoPE can simulate a specific software over a custom platform and obtain estimations of Number of context switches o Thread and process e Total execution time e Processor running time Use of processor Executed instructions Instruction Cache misses Processor energy and power consumption Additional detail about the tool will be presented in the following chapters 2 1 2 M3Plugin MSP is an open source plug in developed to integrate SCoPE within the Design Space Exploration DSE generic flow defined in the european Multicube project The plug in extends the modeling infrastructure to enable the simulation tool to communicate with a design space exploring tool such as modeFrontier http www esteco com or M3Explorer http m3explorer sourceforge net It can be downloaded from http www teisa unican es gim en scope multicube html or from the SCoPE official web site Extended information about the plug in can be found in the user guide at disposal at
18. ent was authorized by Prof Eugenio Villar All contributors from the University of Cantabria Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC Contents EES ERVA S AYA I AART R EET ES E E E seve SEET 5 Z Global SCOPE Mi ras tent 06 5 aay wade elvece tsa cus cess aan Avaes Secale leiciada ceed eee tele 7 21 OPEN SOUTCE components issiria ienke enrii ieoi aeiee ini nnie eainiie tee 7 211 SCOPE simu lation Core serrera ene ae a e T aa E dane E a e EEEa 7 212 M3P lupien ar a a a nent ert eee Pe ne CRT a E S ARE 8 2 2 Non open source COMPONENtS ys cscavisecscacedocasesiuasdevasvdnssdlevessdis sovaansicoeversa uncer s eacesbessedarnaggveanaes 10 2 2 1 Optimized SW estimation PlUG iN ccscccssscetsesrcesscceesccsnesenscessccetscessessnseessscenseeess 10 2 2 2 Cache modeling plug in se a ideas apres epee ana svGae oN nce Siva teu eiPalten guarded 10 2 2 3 IP XACT platform description PlUIG I0 ccs iec nccesentsevcessccenteeschesedensscvedssdeateesstveedeesincadeaes 10 2 24 WATS 2 AUP PSN oon ota cat ateseceatal ten cele T TA E EAST 11 2 2 5 Thermal floor plan analysis plug in seseeseeseseeseesssesseeseessesseeseesresseesessesseesereessseessseee 11 2 2 6 Sicosys network modeling plug in eseesesessessssessesseesserseeseesresseeseestesseeseeseesseeserssseeesseee 11 22 A PEE UU SALT gies Goer cea ya e E A E EE E R RE EE 11 2 2 8 Real Time Linux PUVA cases sa5 tase c
19. ering different HW configurations As the code executed is the same performance information from one simulation can be reused in other simulations with compatible configurations Furthermore performance information obtained with other simulators at different abstraction levels can be used during the exploration process increasing the accuracy of the process e Automatic metric reporting The tool is capable of automatically reporting a list of system metrics following Multicube XML interchange formats The metrics the user wants to be reported must be indicated through a XML file at the beginning of the simulation When a simulation finishes a new XML file with the results is automatically created e Portability The tool is portable across a wide range of systems This goal is achieved by not sacrificing the efficiency of the overall exploration engine The standard ANSI C programming language is used for developing the open source framework The Standard Template Library as well as other open source libraries are used during the development process e Multiple parallel executions The tool has been adapted to allow multiple concurrent executions in different directories with complete independence among them This feature allows the exploration tool to run several instances of the simulation to speed up the exploration process 2 2 Non open source components 2 2 1 Optimized SW estimation plug in SCoPE basic package provides preliminary te
20. hile the XML files are used in the multimedia use case e Automatic system configuration The tool provides a second XML input to easily modify the system configuration in order to perform the DSE process e Exploration through global variables The basic solution for exploring systems is defining unfixed parameters in the XML system description file Nevertheless the tool allows also exploring internal details of the system component models These internal details are characteristics that are described in the model code but without visibility in the XML system description file To allow these exploration the parameters must be declared as global variables in the code files and in the XML files Furthermore this technique allows exploring system described completely in SystemC code not in XML files e Memory space separation for system component models The extended tool is prepared to isolate the memory space of each component model As the tool is developed as a host process running the SystemC kernel only one memory space is provided for the entire simulation Thus duplicating names of global elements result in simulation errors The isolation provided avoids conflicts when using the same names for functions or global variables in several component models Furthermore it allows instantiating the same component several times SW HW communication through direct register memory addresses In embedded systems HW SW communication is usua
21. lly performed letting the SW to access the memory address where the peripheral registers are mapped These addresses are handled as pointers where data are read or stored Previous versions of the tool and in general SystemC based solutions does not support this solutions as it implies trying to access the peripherals of the host machine This refined version provides the features required to support direct pointer access to HW peripherals from SW component models Time and power parameters in generic HW integration wrappers Integration of HW components both generic and user defined ones is done in SCoPE by using generic Integration Wrappers The use of these generic wrappers allows the automatic system model creation Now the wrappers also provide facilities to include time and power information for each component in an standard way Thus components performance effects can be easily integrated in the XML system description file This increases the accuracy of time and power metrics obtained with Multicube SCoPE e Integration of IMEC ARP library for reuse of timing information The Atomium Record Playback library of IMEC has been integrated in Multicube SCoPE This new feature allows storing data from a reference simulation in order to be re used in Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC other simulations During the exploration process multiple simulations of the same code are done consid
22. m interfaces SCoPE integrates a POSIX based API that allows the execution of a large number of software applications that follows this standard POSIX is the main operating system interface nowadays but it is not the unique Thus SCoPE has been improved to support extensions for other types of interfaces An example is the integration with the uC OS interface This is a demonstration of the scalability of the tool in terms of software support The following POSIX libraries has been included in the OS model include mqueue h pthread h sched h semaphore h signal h stdlib h time h unistd h include sys ioctl h select h time h types h wait h Additionally as SCoPE is executed on a Linux UNIX host computer some of the libraries of the host computer can be used such as string h math h stdio h etc In general all functions from the native host OS that are non blocking does not modify scheduling parameters and does not depend on timing can be used To use the functions for handling sockets and TCP IP connections the lwIP plug in is required Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC 3 2 2 Device Drivers In order to enable the integration of HW SW communication the main functions for developing charater device drivers and interrupt handling provided by Linux 2 6 kernels are included in the OS model The main files are the following include asm bitops h dma h io h sigi
23. n is annotated in the code generated an instrumented code containing performance information Then the code is compiled to be natively simulated The tool scope g is an extension of gcc g that perform all the annotation process automatically generating the final binary file Basic Block Characterization Basic Block Table Instrumented e Native Compiler Cache Model Executable bled Figure 2 Estimation process The code performance is analyzed identifying the operations included on each basic block if for The cost of each operator depends on the target processor where the SW is expected to run The costs for each processor are stored in the processors xml file included in the config folder of SCoPE sources The costs are stored for an ideal frequency of 1GHz Additionally the xml information contains a default frequency that can be modified in the sc_main function or dynamically during simulation This frequency is used to make a correction on the annotated costs in order to model the performance of the processor at that frequency The compiler also is in charge of redirect the OS function calls in order to call the SCoPE OS model not the host OS scope g receives all the gcc g required flags for compiling the application SW Additionally it accepts the following scope specific flags SCcope cpu cpu_to_use e g arm926t scope method op cost other plugins enables other S
24. nfo h include linux fs h if_tun h interrupt h ioport h miscdevice h poll h if h init h io h irqreturn h netdevice h_ smp h To load a driver the function insmod must be called in the sc_main function 3 3 HW Platform modeling 3 3 1 Hardware platform simulation SystemC is the language used for the modeling of the hardware platform due to the easiness of implementation C extension and its simulation kernel For the purpose of simulate different platforms SCoPE incorporates some generic hardware modules Bus based on TLM2 used for the communication with peripherals and the transmission of hardware interruptions DMA for coping large amount of data Simple memory for the simulation of cache and DMA traffic Hardware interface for an easy custom hardware connection Network interface that work as a net card for the NoC 3 3 2 System simulation Multi computation One of the advantages of this tool is the possibility of interconnection among independent nodes and simulate the interaction among them Modular structure Each RTOS component is an independent object that does not share any data with the others Furthermore each process is isolated from the rest of the system thus a process with global variables can be replicated in many nodes without data collision problems Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC Copyright 2007 2010 Design of Systems on Silicon
25. re framework including application frameworks that allows software to run Typical platforms include a computer s architecture operating system programming languages and related runtime libraries or graphical user interface Real Time Operating System RTOS Multitasking operating system intended for real time applications Such applications include embedded systems industrial Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC robots spacecraft industrial control and scientific research equipment A RTOS facilitates the creation of a real time system but does not guarantee the final result will be real time this requires correct development of the software Key factors in an RTOS are therefore a minimal interrupt latency and a minimal thread switching latency SW platform Group of generic SW components used to provide the required support to the SW applications System Configuration file XML file defining the values required for the system configuration parameters to perform a simulation System Descriptions file XML file describing the system It contains a description of the HW platform SW platform and SW application System Metrics file XML file where the obtained estimation for the system metrics are reported SystemC Set of library routines and macros implemented in C which makes it possible to simulate concurrent processes ea
26. tabria at http www atc unican es SICOSYS An extension of the plug in has been developed to connect the network modeling tool with SCoPE for accurate modeling of MpSoC NoC systems It allows increasing the accuracy of the simple mesh network model provided with the SCoPE open source infrastructure 2 2 7 TCP IP plug in In order to provide TCP IP capabilities to the OS model provided with SCoPE an extension of the IwIP stack http www sics se adam Iwip adapted to execute within SCoPE simulations is provided The plug in allows modeling TCP connections among the nodes of the system simulated and connecting the simulation with applications running on the host computer and thus accessing the Internet 2 2 8 Real Time Linux plug in Provides an extension of the OS modeling containing the Real Time Linux extensions developed in the Hyades project Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC 3 SCoPE modeling capabilities The SCoPE library provides a complete set of facilities for fast modeling of complex embedded systems The goal of ScoPE is to give the designer the components required to easily create a virtual model of the embedded system in design To do that SCoPE provides element for modeling the both SW and the HW subsystems The SW subsystem is modeled in SCoPE by separating the application SW code and the SW infrastructure operating systems and associated components
27. the web site The main features of the plugin are the following e Dual use of M3P SCoPE as a tool or a library The extended version provides an example independent SCoPE tool executable avoiding manual creation of SystemC standard sc_main functions This capability reduces compilation times and providing a more flexible and user friendly solution Furthermore the possibility of using the code as a library is still maintained e Automatic system model generation The open source tool provides a XML input capable of creating the system models from XML descriptions This capability allows dynamically creating the system models and thus dynamically supporting any system modification that want to be explored by the Design Space Exploration DSE tools As a consequence DSE process can be completely performed without compiling the simulation model and thus reducing the exploration time e Dual input for system descriptions The refined tool has been prepared to accept system descriptions in two formats as a SystemC code or in XML files This extends the capabilities of the initial prototype where Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC only XML description was valid To allow exploration of SystemC code based descriptions the new feature of system configuration through global variables has to be used In the Multicube project the SystemC code is used to model the power line use case w
28. tions of the system components In more detail SCoPE is a C library that extends without modifying the standard language SystemC to perform the co simulation On one side it simulates C C software code over High level Operating System models Currently three different operating system interfaces are supported POSIX win32 and uC OS but modeling other OSs is also possible On the other hand it co simulates these pieces of code with hardware described on SystemC language From that simulation the user obtain a timed simulation of the system which allows to check timing constraints delays timeouts and optimize the occupation of the processing resources Additionally the SW timing modeling allows analyzing the effects of interrupts and HW SW communications in the system operation SCoPE simulation infrastructure is composed of A core with a set of central services provided as open source code and directly accessible from the web site A set of plug ins for specific purposes can be added some of them available from the web and others requiring specific requests to the authors or to scope teisa unican es The following sections describes the entire structure of plugins and the SCoPE open source simulation core in more detail Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC 2 Global SCoPE infr
29. veloped in such way can be connected Nevertheless in order to make the creation and interconnection of HW models easier SCoPE provides HW wrappers The wrappers are e uc_master_base for master devices e uc_master_slave_base for master slave devices such as dma bridges etc e uc_hw_if for slave devices Master interfaces can call the bus using the following functions e this gt m_port gt write void address void data int size e this gt m_port gt read void address void data int size Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC e this gt m_port gt b_transport tlm_generic_payload amp trans sc_time amp delay Slave components can describe their interaction with the bus implementing the following functions e write void address void data int size e read void address void data int size Using these functions the TLM2 protocol is automatically handled 5 3 Generating the sc_main function The description of the system to be simulated is done in the sc_main function In this function is described the HW platform the SW infrastructure and the application SW The structure of a common SCoPE sc_main function is the following include sc_scope h int sc_main int argc char argv Create the SW infrastructure Load the application SW and drivers Describe the HW platform sc_start time Destroy the previously created components return
30. y scope g tool when compiling o Grammatical constraints m Enum Using SCoPE it is no possible to finish a enum declaration with a coma scope g uses a C grammar for analyzing the application SW so grammatical rules not supported in C cannot be accepted Allowed Not allowed enum fruits apple lemon orange enum fruits apple lemon orange 6 2 General restriction on the code for the native simulation o Use of libraries All you want to simulate must be source code If we have a binary code object code or library compiled for the target CPU we will not can simulate it This has its drawbacks namely that there are many companies whose code is closed and all you have are the libraries compiled and a series of headers We have to give the sources in C C o Pragmas advanced directives and compiler attributes Many codes use pragmas and directives that are specific to each compiler As advice to avoid any problem related to this you can request that both codes the one at the target CPU and the one at the workstation respect the ANSI standard C It is highly recommended Copyright 2007 2010 Design of Systems on Silicon DS2 and University of Cantabria UC when you are working in real time critical applications where reliability must be maximum 7 Bugs and suggestions Please report bugs and suggestions about this document or about the SCoPE tool to scope teisa unican es Copyright
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