Hi Michael, Cool! I was indeed using fifo because qthreads doesn't compile on ARM (yet?). I will give the int variant a try to see how they perform.
Also, I've been working on a version of the same code that uses your feedback. Here's the not-fully-tested variant. I'm also working on a variant that doesn't use Partitions at all, which should produce the simplest and fastest variant of all. On Wed, May 20, 2015 at 12:26 PM, Michael Ferguson <[email protected]> wrote: > Hi Brian - > > I tried running two different simplified versions of your program > on my laptop, using GASNET with the UDP conduit. > > One version uses strings (as you had). The other version replaces > the strings with uints but is conceptually the same. > > This table summarizes my results for 100 iterations: > > on my laptop (GASNet UDP, qthreads): > 1 locale 2 locales > string 0.000147 s 8.502195 s -> 50,000x slower > uint 0.000024 s 0.000029 s -> 1.2x slower > > on a linux server (GASNet UDP, qhtreads): > 1 locale 2 locales > string 0.000311 s 0.013721 s -> 44x slower > uint 0.000016 s 0.000035 s -> 2x slower > > > But, if I change to CHPL_TASKS=fifo, I get this table: > > on my laptop (GASNet UDP, fifo): > 1 locale 2 locales > string 0.000129 s 0.003669 s -> 28x slower > uint 0.000024 s 0.000032 s -> 1.3x slower > > > on a linux server (GASNet UDP, fifo): > 1 locale 2 locales > string 0.000144 s 0.001600 s -> 11x slower > uint 0.000015 s 0.000026 s -> 1.7x slower > > > > I'm seeing similar, but not as severe problems with > a real distributed system. Since the problem is not > nearly as severe with CHPL_TASKS=fifo, I think that > there is a problem qthreads and GASNet. > > That's in addition to string problems we already > know about. > > Brian, were you using CHPL_TASKS=fifo on the > ARM cluster when seeing the performance problem? > > I've attached the programs I was using in these experiments. > > Thanks, > > -michael > > > > >
crosstalk_replicated.chpl
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