README revision 11971
1This directory contains a demo of a coupling between gem5 and SystemC-TLM.  It
2is based on the gem5-systemc implementation in utils/systemc. This Readme gives
3an overall overview (I), describes the source files in this directory (II),
4explains the build steps (III), shows how to run example simulations (IV-VI)
5and lists known issues (VII).
6
7
8I. Overview
9===========
10
11The sources in this directory provide three SystemC modules that manage the
12SystemC/gem5 co-simulation: Gem5SimControl, Gem5MasterTransactor, and
13Gem5SlaveTransactor. They also implement gem5's ExternalMaster::Port interface
14(SCMasterPort) and ExternalSlave::Port interface (SCSlavePort).
15
16**SCMasterPort** and **Gem5MasterTransactor** together form a TLM-to-gem5
17bridge. SCMasterPort implements gem5's ExternalMaster::Port interface and forms
18the gem5 end of the bridge. Gem5MasterTransactor is a SystemC module that
19provides a target socket and represents the TLM side of the bridge. All TLM
20requests send to this target socket, are translated to gem5 requests and
21forwarded to the gem5 world through the SCMasterPort. Then the gem5 world
22handles the request and eventually issues a response. When the response arrives
23at the SCMasterPort it gets translated back into a TLM response and forwarded
24to the TLM world through target socket of the Gem5MasterTransactor.
25SCMasterPort and Gem5MasterTransactor are bound to each other by configuring
26them for the same port name.
27
28**SCSlavePort** and **Gem5SlaveTransactor** together form a gem5-to-TLM bridge.
29Gem5SlaveTransactor is a SystemC module that provides a initiator socket and
30represents the TLM end of the bridge. SCSlavePort implements gem5's
31ExternalSlave::Port interface and forms the gem5 side of the bridge. All gem5
32requests sent to the SCSlavePort, are translated to TLM requests and forwarded
33to the TLM world through the initiator socket of the Gem5SlaveTransactor. Then
34the TLM world handles the request and eventually issues a response. When the
35response arrives at the Gem5SlaveTransactor it gets translated back into a
36gem5 response and forwarded to the gem5 world through the SCSlavePort. SCSLavePort
37and Gem5SlaveTransactor are bound to each other by configuring them for the
38same port name.
39
40**Gem5SimControl** is the central SystemC module that represents the complete
41gem5 world. It is responsible for instantiating all gem5 objects according to a
42given configuration file, for configuring the simulation and for maintaining
43the gem5 event queue. It also keeps track of all SCMasterPort and SCSlavePort
44and responsible for connecting all Gem5MasterTransactor and Gem5SlaveTransactor
45modules to their gem5 counterparts. This module must be instantiated exactly
46once in order to run a gem5 simulation from within an SystemC environment.
47
48
49II. Files
50=========
51
52    sc_slave_port.{cc,hh}     -- Implements SCSlavePort
53    sc_master_port.{cc,hh}    -- Implements SCMasterPort
54    sc_mm.{cc,hh}             -- Implementation of a TLM memory manager
55    sc_ext.{cc,hh}            -- TLM extension that carries a gem5 packet
56    sc_peq.{cc,hh}            -- TLM PEQ for scheduling gem5 events
57    sim_control.{cc,hh}       -- Implements Gem5SimControl
58    slave_transactor.{cc,hh}  -- Implements Gem5SlaveTransactor
59    master_transactor.{cc,hh} -- Implements Gem5MasterTransactor
60
61    example/common/cli_parser.{cc,hh}     -- Simple cli argument parser
62    example/common/report_hanlder.{cc,hh} -- Custom SystemC report handler
63
64    example/slave_port/main.cc           -- demonstration of the slave port
65    example/slave_port/sc_target.{cc,hh} -- an example TLM LT/AT memory module
66    example/slave_port/tlm.py            -- simple gem5 configuration
67    example/slave_port/tlm_elastic.py    -- gem5 configuration with an elastic
68                                            trace replayer
69    example/slave_port/tgen.cfg          -- elastic traceplayer configuration
70
71    example/master_port/main.cc          -- demonstration of the master port
72    example/master_port/traffic_generator.{cc/hh}
73                                         -- an example traffic generator module
74    example/master_port/tlm.py           -- simple gem5 configuration
75
76Other Files will be used from utils/systemc example:
77
78    sc_logger.{cc,hh},
79    sc_module.{cc,hh},
80    sc_gem5_control.{cc,hh},
81    stats.{cc,hh}
82
83
84III. Build
85==========
86
87First build a normal gem5 (cxx-config not needed, Python needed).
88Second build gem5 as a library with cxx-config support and (optionally)
89without python.
90
91> cd ../..
92> scons build/ARM/gem5.opt
93> scons --with-cxx-config --without-python --without-tcmalloc \
94>       build/ARM/libgem5_opt.so
95> cd util/tlm
96
97Note: For MAC / OSX this command should be used:
98> scons --with-cxx-config --without-python --without-tcmalloc \
99>       build/ARM/libgem5_opt.dylib
100
101Set a proper LD_LIBRARY_PATH e.g. for bash:
102> export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/path/to/gem5/build/ARM/"
103
104or for MAC / OSX:
105> export DYLD_LIBRARY_PATH="$DYLD_LIBRARY_PATH:/path/to/gem5/build/ARM/"
106
107The build system finds your SystemC installation using pkg-config. Make sure
108that pkg-config is installed and your systemc.pc is within your
109PKG_CONFIG_PATH. You can add SystemC to the PKG_CONFIG_PATH using the following
110command:
111> export PKG_CONFIG_PATH="/path/to/systemc/lib-<arch>/pkgconfig/:$PKG_CONFIG_PATH"
112
113To build one of the examples:
114
115> cd examples/{master,slave}_port
116> scons
117> cd ../../
118
119
120IV. Simple Examples
121===================
122
123> cd examples/{master,slave}_port
124
125In order to run our example simulation, we first need to create a config.ini
126that represents the gem5 configuration. We do so by starting gem5 with the
127desired python configuration script.
128
129> ../../../../build/ARM/gem5.opt ./tlm.py
130
131The message "fatal: Can't find port handler type 'tlm_{master,slave}'" is okay.
132The configuration will be stored in the m5out/ directory
133
134The build step creates a binary gem5.opt.sc in the example directory.  It can
135now be used to load in the generated configuration file from the previous
136normal gem5 run.
137
138Try:
139
140> ./gem5.opt.sc m5out/config.ini -e 1000000
141
142It should run a simulation for 1us.
143
144To see more information what happens inside the TLM modules use the -v flag:
145
146> ./gem5.opt.sc m5out/config.ini -e 1000000 -v
147
148To see more information about the port coupling use:
149
150> ./gem5.opt.sc m5out/config.ini -e 1000000 -d ExternalPort
151
152
153V. Full System Setup
154=====================
155
156Apart from the simple examples, there is a full system example that uses
157the gem5-to-TLM bridge.
158
159>cd examples/slave_port
160
161Build gem5 as described in Section III. Then, make a config file for the
162C++-configured gem5 using normal gem5
163
164> ../../../../build/ARM/gem5.opt ../../../../configs/example/fs.py   \
165  --tlm-memory=transactor --cpu-type=timing --num-cpu=1              \
166  --mem-type=SimpleMemory --mem-size=512MB --mem-channels=1 --caches \
167  --l2cache --machine-type=VExpress_EMM                              \
168  --dtb-filename=vexpress.aarch32.ll_20131205.0-gem5.1cpu.dtb        \
169  --kernel=vmlinux.aarch32.ll_20131205.0-gem5                        \
170  --disk-image=linux-aarch32-ael.img
171
172The message "fatal: Can't find port handler type 'tlm_slave'" is okay.
173The configuration will be stored in the m5out/ directory
174
175The binary 'gem5.opt.sc' can now be used to load in the generated config
176file from the previous normal gem5 run.
177
178Try:
179
180> ./gem5.opt.sc m5out/config.ini -o 2147483648
181
182The parameter -o specifies the begining of the memory region (0x80000000).
183The system should boot now.
184
185For convenience a run_gem5.sh file holds all those commands
186
187
188VI. Elastic Trace Setup
189========================
190
191Elastic traces can also be replayed into the SystemC world.
192For more information on elastic traces please refer to:
193
194 - http://www.gem5.org/TraceCPU
195
196 - Exploring System Performance using Elastic Traces:
197   Fast, Accurate and Portable
198   R. Jagtap, S. Diestelhorst, A. Hansson, M. Jung, N. Wehn.
199   IEEE International Conference on Embedded Computer Systems Architectures
200   Modeling and Simulation (SAMOS), July, 2016, Samos Island, Greece.
201
202Similar IV. the simulation can be set up with this command:
203
204> ../../../../build/ARM/gem5.opt ./tlm_elastic.py
205
206Then:
207
208> ./gem5.opt.sc m5out/config.ini
209
210
211VII. Knwon issues
212=================
213
214* For some toolchains, compiling libgem5 with tcmalloc leads to errors
215  ('tcmalloc Attempt to free invalid pointer xxx') when linking libgem5 into a
216  SystemC application.
217* When SystemC was build with --enable-pthreads, SystemC applications linked
218