Hi Yao, Long-term, yes, the performance of gem5 is something that is important to improve! We often hear this as one of our most wanted features. However, because of the way gem5 was designed and has evolved over time, *parallelizing* it will be very, very difficult. There are just too many places where we have pointers between objects to easily apply parallel discrete event simulation methodology.
Even if we could parallelize gem5, I would not expect more than a 2-4x performance improvement. I'm not convinced there's that much potential for independent work (again, because of the underlying design of gem5). So, even if we could scale gem5 to multiple cores, simulating all of a SPEC CPU ref run would be unlikely in a reasonable amount of time. Not to mention, when the next version of SPEC CPU comes out it will be even longer! Cheers, Jason On Tue, Nov 8, 2022 at 5:53 PM yaogang <yaogan...@hisilicon.com> wrote: > Hi Jason, > > > > Is there any roadmap (near future not long term) to take gem5 to multi > thread accerleration? > > > > Regards > > Yao > > > > *发件人:* Jason Lowe-Power via gem5-users [mailto:gem5-users@gem5.org] > *发送时间:* 2022年11月9日 3:02 > *收件人:* The gem5 Users mailing list <gem5-users@gem5.org> > *抄送:* Markus Bichl <e1625...@student.tuwien.ac.at>; Jason Lowe-Power < > ja...@lowepower.com> > *主题:* [gem5-users] Re: SPEC CPU 2017 taking days to simulate > > > > Hi Markus, > > > > I would expect gem5 to be at least 10,000-100,000x slower than your host. > So, if it takes 100 seconds on the host, then I would > expect between 1,000,000 and 10,000,000 seconds or more! > > > > That's 277-2770 hours or 10-100 days!! > > > > BTW, I actually think a 10-100,000x slowdown is on the low side if you're > simulating multiple cores and/or using the out-of-order CPU model. > > > > In other words, running ref in gem5 to completion is not feasible :). > There are techniques like SimPoint and other sampling methodologies that > can help, but they come with tradeoffs, too. We're working to get some > resources available to easily use sampling methodologies as well. > > > > Cheers, > > Jason > > > > On Tue, Nov 8, 2022 at 10:19 AM Markus Bichl via gem5-users < > gem5-users@gem5.org> wrote: > > Dear gem5 users, > > > > I’m currently running SPEC CPU 2017 benchmarks. I was succesful creating a > SPEC CPU 2017 disk image from this tutorial: > https://gem5.googlesource.com/public/gem5-resources/+/refs/heads/stable/src/spec-2017/ > > > I used this image to start 3 benchmark runs on 3 different systems > (server instance, desktop computer, and my laptop) 2 days ago. All of the > systems have Intel Core/Xeon CPUs (but 5-7 years old), and 16 GBytes of > DDR4 RAM. > > At this time, CPU load is 100% on one core for each system, at least 5 > Gbytes of free memory. > > I started benchmarks using these commands: > > ./build/X86/gem5.fast > ./configs/example/gem5_library/x86-spec-cpu2017-benchmarks.py --image > /home//Projects/spec-2017/spec-2017-image/spec-2017 --partition 1 > --benchmark 625.x264_s --size ref > > ./build/X86/gem5.fast > ./configs/example/gem5_library/x86-spec-cpu2017-benchmarks.py --image > /home//Projects/spec-2017/spec-2017-image/spec-2017 --partition 1 > --benchmark 600.perlbench_s --size ref > > ./build/X86/gem5.fast > ./configs/example/gem5_library/x86-spec-cpu2017-benchmarks.py --image > /home//Projects/spec-2017/spec-2017-image/spec-2017 --partition 1 > --benchmark 502.gcc_r --size test > > > > I wanted to have the results as fast as possible, so I used gem5.fast, and > also tried the gcc benchmark with the test workload. > > As I do not see any progess on the benchmarks yet, I feel there is > something wrong. Is this a normal simulation time for SPEC CPU 2017 > benchmarks? Is it possible to track the progress of the simulations, even > with "m5.disableAllListeners()” enabled in the system configuration? > > A run of 600.perlbench_s using the ref workload directly on the host > system (server instance) took 181 seconds. > > Thanks a lot for your help! > > > > BR, > > Markus Bichl > > > > Student, Technische Universität Wien > > _______________________________________________ > gem5-users mailing list -- gem5-users@gem5.org > To unsubscribe send an email to gem5-users-le...@gem5.org > >
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