96091f358b
There are 2 problems with the existing checkpoint and restore code in ruby. The first is that when the event queue is altered by ruby during serialization, some events that are currently scheduled cannot be found (e.g. the event to stop simulation that always lives on the queue), causing a panic. The second is that ruby is sometimes serialized after the memory system, meaning that the dirty data in its cache is flushed back to memory too late and so isn't included in the checkpoint. These are fixed by implementing memory writeback in ruby, using the same technique of hijacking the event queue, but first descheduling all events that are currently on it. They are saved, along with their scheduled time, so that the event queue can be faithfully reconstructed after writeback has finished. Events with the AutoDelete flag set will delete themselves when they are descheduled, causing an error when attempting to schedule them again. This is fixed by simply not recording them when taking them off the queue. Writeback is still implemented using flushing, so the cache recorder object, that is created to generate the trace and manage flushing, is kept around and used during serialization to write the trace to disk. Committed by: Nilay Vaish <nilay@cs.wisc.edu> |
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SConstruct |
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.