Thanks, Aji,
I've verified that it was configured with "--enable-guard-pages" by default
when I built Chapel. But is that necessary for Chapel? Any thoughts from
Chapel? I don't want to take the risk of correctness for performance.
Thanks
On Tue, Aug 15, 2017 at 4:50 PM, Aji, Ashwin <[email protected]> wrote:
> These are my 2 cents on measuring qthreads performance before in Chapel.
> If you configured qthreads with “--enable-guard-pages”, then the
> performance will be much slower than without enabling guard pages. It may
> be worthwhile to see how you have configured qthreads.
>
>
>
> Regards,
>
> Ashwin
>
>
>
> *From:* Hui Zhang [mailto:[email protected]]
> *Sent:* Tuesday, August 15, 2017 11:50 AM
> *To:* Greg Titus <[email protected]>
> *Cc:* Chapel Sourceforge Developers List <chapel-developers@lists.
> sourceforge.net>
> *Subject:* Re: [Chapel-developers] qthreads performance
>
>
>
> Hi, Greg
>
>
>
> On Tue, Aug 15, 2017 at 1:35 PM, Greg Titus <[email protected]> wrote:
>
> Hello Hui --
>
> Generally CHPL_TASKS=qthreads outperforms CHPL_TASKS=fifo at all but the
> smallest scales. We would need to know a lot more to come to any
> worthwhile conclusions. What is the output of `printchplenv --anonymize`
> for your configurations (I assume they differ only in terms of the
> CHPL_TASKS setting)?
>
>
>
> CHPL_TARGET_PLATFORM: linux64
>
> CHPL_TARGET_COMPILER: gnu
>
> CHPL_TARGET_ARCH: native *
>
> CHPL_LOCALE_MODEL: flat
>
> CHPL_COMM: gasnet *
>
> CHPL_COMM_SUBSTRATE: ibv *
>
> CHPL_GASNET_SEGMENT: large
>
> CHPL_TASKS: qthreads
>
> CHPL_LAUNCHER: gasnetrun_ibv *
>
> CHPL_TIMERS: generic
>
> CHPL_UNWIND: none
>
> CHPL_MEM: jemalloc
>
> CHPL_MAKE: gmake
>
> CHPL_ATOMICS: intrinsics
>
> CHPL_NETWORK_ATOMICS: none
>
> CHPL_GMP: gmp
>
> CHPL_HWLOC: hwloc
>
> CHPL_REGEXP: re2
>
> CHPL_WIDE_POINTERS: struct
>
> CHPL_AUX_FILESYS: none
>
> Yes, the only difference is CHPL_TASKS.
>
>
>
> Are you using any compilation options other than ‘--fast’? What execution
> options are you using?
>
> For hpl: --n=500 --printArray=false --printStacts=true
> --useRandomSeed=false -nl *
>
> For lulesh:
>
>
>
> --filename=lmeshes/sedov15oct.lmesh -nl *
>
> For isx: --nide-weakISO --n=5592400 --numTrials=10 -nl *
>
> Are you setting any execution-time environment variables (CHPL_RT_*) and
> if so, to what values?
>
> NO
>
>
>
> And finally, what is the target architecture (number of nodes, number of
> CPU cores per node, etc.)?
>
> I use 2/4/8/16/32 nodes, each has 20 physical cores
>
>
>
>
> thanks,
> greg
>
>
>
> > On Aug 15, 2017, at 9:59 AM, Hui Zhang <[email protected]> wrote:
> >
> > Hello,
> >
> > I did some performance comparison between qthreads and fifo with 3
> benchmakrs: lulesh, hpl, and isx. I expected qthreads to outperform fifo in
> all cases, but the result turns out to be superising.
> > For lulesh and hpl, in all tests (#nodes from 2 to 32), qthreads is much
> slower (took 1.5~10x longer than that of fifo). For isx, qthreads beats
> fifo with speedup of 1.5~2x.
> >
> > All benchmarks compiled with --fast and I'm using 1.15. So is what I'm
> getting here reasonable? Any previous performance comparison between fifo
> and qthreads on those benchmarks?
> >
> > Thanks
> >
> > --
> > Best regards
> >
> >
> > Hui Zhang
>
> > ------------------------------------------------------------
> ------------------
> > Check out the vibrant tech community on one of the world's most
> > engaging tech sites, Slashdot.org! http://sdm.link/slashdot______
> _________________________________________
> > Chapel-developers mailing list
> > [email protected]
> > https://lists.sourceforge.net/lists/listinfo/chapel-developers
>
>
>
>
>
> --
>
> Best regards
>
>
> Hui Zhang
>
--
Best regards
Hui Zhang
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