UNIVERSITA’ POLITECNICA DELLE MARCHE, ANCONA (ITALY) Massimo Conti, Giovanni Vece TRANSACTION LEVEL POWER ANALYSIS WITHIN SYSTEMC/TLM APPLICATIONS 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

INTRODUCTORY OVERVIEW PKtool (Power Kernel tool) is a power analysis tool developed by Università Politecnica delle Marche. Mainly dedicated to power estimations for systems modelled in SystemC/C++ language. Entirely realized in SystemC/C++, as a language extension for power analysis. Recently refined for transaction level power estimations in application with the SystemC TLM 2.0 framework. 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

MAIN MOTIVATIONS Power dissipation represents a primary design issue, making it worthwhile to explore possible SystemC extensions for power analysis. Providing an istrument for direct power analysis within a SystemC-based design, Promoting the diffusion and use of the SystemC language. basic language verification library AMS extension TLM framework customized user extensions SystemC power analysis extension 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

APPLICATION MODALITIES PKtool can be applied on the single sc_modules constituting a SystemC description. The simulation results are given by the power/energy estimations of each monitored sc_module, reported in apposite text files. sc_module #1 sc_module #4 sc_module #3 sc_module #2 SYSTEMC DESCRIPTION SIMULATION RESULTS PKTOOL SIMULATOR POWER ESTIMATION #1 POWER ESTIMATION #2 POWER ESTIMATION #3 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

INSTANCE OF POWER_MODULES sc_module #1 sc_module #4 sc_module #3 sc_module #2 ORIGINAL SYSTEMC DESCRIPTION SYSTEMC DESCRIPTION WITH POWER_MODULES power_module #1 power_module #4 power_module #3 power_module #2 POWER_MODULE INSTANCE 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton Instance example : master m1, m2; POWER_MODULE(master) m1,m2;

POWER MODELS IN PKTOOL ENVIRONMENT Formal representations of the power dissipated by a digital system (usually an approximation of the real dissipation). PKtool handles power models through a behavioural interface of general validity. PKtool makes available several power models included inside a default model library. signal-based power models table-based power models operator-based power models transaction level power models PKtool model library 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

SYSTEMC DESCRIPTION WITH POWER_MODULES power_module #1 power_module #4 power_module #3 power_module #2 POWER MODEL SELECTION Each power_module is associated to power models of the PKtool model library. The association task is carried out via an interactive procedure, at the beginning of a simulation. PKTOOL MODEL LIBRARY power model #1 power model #2 power model #4 power model #3 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

PKTOOL SIMULATION FLOW A PKtool simulation takes place during an ordinary SystemC simulation of the system. The power estimations are referred to the system evolution reproduced in the SystemC simulation. power estimation Start of SystemC simulation End of SystemC simulation time PKtool simulation SystemC simulation model data power model data 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

EXTENSION FOR TRANSACTION LEVEL POWER ANALYSIS (PKTOOL/TLM) The latest PKtool evolution has led to an extension for transaction level power estimations. Applicable on system models realized through the TLM 2.0 framework of SystemC language (SystemC/TLM). Conceptually derived from research studies on estimation methodologies at transaction level. Analysis modalities fitting the simulation modalities in SystemC/TLM. 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

IMPLEMENTATION APPROACH BENEFITS: unified design context, no need of ad hoc execution tools,,. wide chances for interoperability and user enhancements, C++ language standard SystemC basic language SystemC/TLMBasic PKtool PKtool/TLM framework PKtool/TLM is implemented according to a typical SystemC modeling paradigm: 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

MODULE INTERACTIONS IN SYSTEMC/TLM Communications based on interface function calls. Logical roles: initiator, target, interconnect unit. Functional roles: caller, callee. Initiator Target Interconnect component 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

TRANSPORT INTERFACES IN SYSTEMC/TLM Transport Interfaces Functions tlm_blocking_transport_if b_transport(.) tlm_fw_nonblocking_transport_if nb_transport_fw(.) tlm_fw_nonblocking_transport_if nb_transport_bw(.) tlm_fw_direct_mem_if get_direct_mem_ptr(.) tlm_fw_direct_mem_if invalidate_direct_mem_ptr(.) tlm_transport_dbg_if transport_dbg(.) 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

ESTIMATION APPROACH AT MODULE LEVEL An interface function call implies an energy dissipation for the caller and callee modules. The overall energy dissipation of a module can be estimated as the sum of the energy costs of the related function calls. CALLER MODULE CALLEE MODULE Interface function. call energy dissipation 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

ASSOCIATION BETWEEN INTERFACE FUNCTIONS AND POWER MODELS b_transport( ) nb_transport_fw( ) nb_transport_bw( ) … SYSTEMC/TLM MODULE power model INTERFACE FUNCTIONS 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

POWER MODELS IN PKTOOL/TLM PKtool/TLM provides some transaction level power models directly applicable in power estimations. Targeted to estimate the energy dissipation of an interface function call. Conceptually derived from estimation methodologies at transaction level. Application modalities fitting with the simulation dynamics in SystemC/TLM. 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

FORMULAS APPLIED FOR POWER ESTIMATIONS The overall energy estimation of a monitored module is achieved through the following formulas: 1) basic: E mod = 2) more complete: E mod = + N = function calls E i = energy dissipations per function call P st = static power dissipation M = idle periods T j = idle times Σ N i =1 EiEi Σ EiEi Σ j =1 P st T j M idle active phase active phase simulation time 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton N

CONFIGURATION STEPS FOR PKTOOL/TLM ANALYSIS A system module can be configured for PKtool/TLM analysis through the following main steps: a) definition and istance of a related power_module. b) selection of the interface functions to be monitored. c) specification of a power model for each selected functions. The steps a) and c) are carried out with the same modalities of a basic PKtool analysis. 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

SELECTION OF INTERFACE FUNCTIONS / 1 The selection of an interface function distinguish two possible cases: 1) Functions concerning the module as callee. POWER_MODULE_CLASS(example_mod)‏ {... PK_NB_TRANSPORT_FW_2 PK_GET_DIRECT_MEM_PTR_2 } Select the functions nb_transport_fw(.) and get_direct_mem_ptr(.) implemented by the module 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

SELECTION OF INTERFACE FUNCTIONS / 2 2) Functions concerning the module as caller. SC_MODULE(example_mod) {... tlm::tlm_initiator_socket<> init_sock; } POWER_MODULE_CLASS(example_mod) {... PK_NB_TRANSPORT_FW_1(target_sock) } Select the functions nb_transport_fw(.) called via init_sock 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

ANALYSIS RESULTS /1 At the end of a PKtool/TLM simulation, the analysis results are reported in distinct text files. Each result file is associated to a specific power_module. Example: overall simulation period: [ ps] POWER/ENERGY DISSIPATION OF IMPLEMENTED TLM FUNCTIONS function: nb_transport_bw function calls = 128 energy estimation = 1.53e-005 J average power estimation = 8.32e-013 W 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton

ANALYSIS RESULTS /2 POWER/ENERGY DISSIPATION OF SOCKET TLM FUNCTIONS SOCKET: initiator_socket function: b_transport function calls = 133 energy estimation = 3.43e-005 J average power estimation = 1.86e-012 W function: nb_transport_fw function calls = 128 energy estimation = 2.56e-005 J average power estimation = e-012 W STATIC DISSIPATION energy estimation: 1.844e-005J OVERALL ENERGY ESTIMATION: 9.36e-005J

PKTOOL REFERENCES ON THE WEB 22. European SystemC User’s Group Meeting, September 14th, 2010, Southampton PKtool/TLM will be soon distributed as free of charge open source releases Downloadable from: Included in the release PKtool 2.2 beta-8