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 <[email protected]>
Subject: Re: [Chapel-developers] qthreads performance
Hi, Greg
On Tue, Aug 15, 2017 at 1:35 PM, Greg Titus
<[email protected]<mailto:[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]<mailto:[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
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--
Best regards
Hui Zhang
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