Hi Fulya, The PARSEC benchmarks on the disk image from our site don't explicitly set thread affinity, but instead rely on Linux to schedule the threads. If you are having trouble with load balancing across cores, I can recommend a couple things:
1) Add an extra core, but do not increase the number of threads. One common problem with both Pthreads and OpenMP is that Linux generally doesn't handle the master thread, which spawns other threads, the same way as the other threads. Because of this and a small set of background processes, Linux gets finicky with thread scheduling when the number of active threads is equal to the number of cores. 2) Increase your input set sizes. This is the most common issue with load imbalance, namely there isn't enough work to keep numerous threads busy. I'd recommend using at least the simmedium inputs, though for many benchmarks, simlarge is more substantial. From experience, canneal is the only benchmark that has major load balancing even after you do the above things. Hope this helps, Joel On Tue, Sep 17, 2013 at 12:05 AM, Fulya Kaplan <fkapl...@bu.edu> wrote: > Hi, > I am running parsec on X86, using gem5-stable-07352f119e48. I am using the > precompiled Parsec image and kernel image provided on Parsec website. I > have seen an obvious imbalance in the cpu statistics (such as IPS) even for > the 2 core case. > To bind each thread to a core, thus to make sure they are balanced, I want > to use "set affinity" functionality. I have some questions regarding that: > 1) Is there a way to do that for all the Parsec benchmarks without > recompiling anything? > 2) What are some options that I can follow? > 3) I found this thread suggesting to use export GOMP_CPU_AFFINITY="0 1 2 > 3" > http://www.mail-archive.com/gem5-users@gem5.org/msg04627.html > But it also says I can only use it with OpenMP benchmarks, which deos not > cover all Parsec benchmarks. If I am restoring from a checkpoint, can I > still use that command (because I assume that command should be put into > the .rcS file which is executed upon kernel boot) ? > Could anyone help me on those issues? > Best, > Fulya Kaplan > > > _______________________________________________ > gem5-users mailing list > gem5-users@gem5.org > http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users > -- Joel Hestness PhD Student, Computer Architecture Dept. of Computer Science, University of Wisconsin - Madison http://pages.cs.wisc.edu/~hestness/
_______________________________________________ gem5-users mailing list gem5-users@gem5.org http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users
