7a94f5cbf7
Each instance of simgen uses a license. If there are only so many to go around, running many instances at once could exhaust the pool of licenses and break the build. The number of licenses may be less than the number of regular build steps we want to do in parallel, but may be greater than zero. To limit them to at most n in parallel where n might be less than j and/or more than 1, we create a group of license slots, assign simgen invocations to a slot, and then use scons's side effect mechanism to ensure no two invocations in the same slot run at the same time. This may be a suboptimal packing if the commands take significantly different amounts of time to run since the slots are preallocated and not demand allocated, but the difference shouldn't normally matter in practice, and scons doesn't provide a better mechanism for partially serializing certain build steps. Change-Id: Ifae58b48ae1b989c1915444bf7564f352f042305 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/32124 Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu> Maintainer: Gabe Black <gabeblack@google.com> Tested-by: kokoro <noreply+kokoro@google.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/about, and for more information about building the simulator and getting started please see http://www.gem5.org/documentation and http://www.gem5.org/documentation/learning_gem5/introduction. 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/documentation/general_docs/building 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 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/documentation/general_docs/building for more details and options. 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. If you have questions, please send mail to gem5-users@gem5.org Enjoy using gem5 and please share your modifications and extensions.