1This directory contains a connector that allows gem5 to be used as a
2component in SST (Structural Simulation Toolkit, sst-simulator.org). More
3specifically, it creates a .so that wraps the libgem5_*.so library. At a
4high level, this allows memory traffic to pass between the two simulators.
5SST Links are roughly analogous to gem5 Ports, although Links do not have
6a notion of master and slave. This distinction is important to gem5, so
7when connecting a gem5 CPU to an SST cache, an ExternalSlave must be used,
8and similarly when connecting the memory side of SST cache to a gem5 port
9(for memory <-> I/O), an ExternalMaster must be used.
10
11The connector handles the administrative aspects of gem5
12(initialization, simulation, shutdown) as well as translating
13SST's MemEvents into gem5 Packets and vice-versa.
14
15Step-by-step instructions:
16
170. install SST and its dependencies
18
19Note: the Makefile assumes you installed from an SVN checkout, not a release.
20If you install a release, modify SST_VERSION at the top of the Makefile.
21
220b. set/append to the PKG_CONFIG_PATH variable the path where SST installed
23    its pkgconfig, if not in a system-wide location.
24
25Then from gem5 root:
26
271. build gem5 library:
28% scons build/ARM/libgem5_opt.so
29
30Note: if you would rather use a fast, debug, etc. variant instead,
31modify GEM5_LIB at the top of the Makefile.
32
332. build gem5 SST component:
34% make -C ext/sst
35
363. run SST like so:
37% sst --add-lib-path <path to ./ext/sst> <config script, e.g. ext/sst/*.py>
38
39===========
40
41Note: if you want to use an arch other than ARM (not tested/supported),
42tweak the Makefile to get includes from that build directory instead.
43
44===========
45
46This directory provides:
471. an SST "Component" for gem5;
482. a class that implements gem5's "ExternalMaster" interface to connect with
49   SST "Link"s exchanging "memEvents"
50   (sst/elements/memHierarchy stuff - caches, memories, etc.)
51   This lets gem5 receive packets from SST, as in
52   an SST LL$ (a master external to gem5) <-> I/O devices.
533. a class that implements gem5's "ExternalSlave" interface to connect with
54   SST "Link"s exchanging "memEvents" once again with the packet flow reversed:
55   gem5 CPU <-> SST L1 cache (a slave external to gem5)
564. an example configuration that uses both as follows:
57   gem5 CPUs
58       ^
59       | [ExternalSlave]
60       v
61   SST cache hierarchy <-> SST memory
62       ^
63       | [ExternalMaster]
64       v
65   gem5 I/O devices (terminal, disk, etc.)
66