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The AtomicSimpleCPU used to be able to access memory directly to speed up simulation if no caches are used. This is fine as long as no switching between CPU models is required. In order to switch to a new CPU model that requires caches, we currently need to checkpoint the system and restore it into a new configuration. The new 'atomic_noncaching' memory mode provides a solution that avoids this issue since caches are bypassed in this mode. This changeset removes the old fastmem option from the AtomicSimpleCPU and introduces a new CPU, NonCachingSimpleCPU, which derives from the AtomicSimpleCPU. The NonCachingSimpleCPU uses the same mechanism as the AtomicSimpleCPU used to use when accessing memory in when fastmem was enabled. This changeset also introduces a new switcheroo test that tests switching between a NonCachingSimpleCPU and a TimingSimpleCPU with caches. Change-Id: If01893f9b37528b14f530c11ce6f53c097582c21 Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/12419 Reviewed-by: Jason Lowe-Power <jason@lowepower.com> Maintainer: Jason Lowe-Power <jason@lowepower.com>
This is the gem5 simulator. The main website can be found at http://www.gem5.org A good starting point is http://www.gem5.org/Introduction, and for more information about building the simulator and getting started please see http://www.gem5.org/Documentation and http://www.gem5.org/Tutorials. To build gem5, you will need the following software: g++ or clang, Python (gem5 links in the Python interpreter), SCons, SWIG, zlib, m4, and lastly protobuf if you want trace capture and playback support. Please see http://www.gem5.org/Dependencies for more details concerning the minimum versions of the aforementioned tools. Once you have all dependencies resolved, type 'scons build/<ARCH>/gem5.opt' where ARCH is one of ALPHA, ARM, NULL, MIPS, POWER, SPARC, or X86. This will build an optimized version of the gem5 binary (gem5.opt) for the the specified architecture. See http://www.gem5.org/Build_System for more details and options. With the simulator built, have a look at http://www.gem5.org/Running_gem5 for more information on how to use gem5. The basic source release includes these subdirectories: - configs: example simulation configuration scripts - ext: less-common external packages needed to build gem5 - src: source code of the gem5 simulator - system: source for some optional system software for simulated systems - tests: regression tests - util: useful utility programs and files To run full-system simulations, you will need compiled system firmware (console and PALcode for Alpha), kernel binaries and one or more disk images. Please see the gem5 download page for these items at http://www.gem5.org/Download If you have questions, please send mail to gem5-users@gem5.org Enjoy using gem5 and please share your modifications and extensions.