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Re: [charm] perf data in charm++


Chronological Thread 
  • From: Noel Keen <ndkeen AT lbl.gov>
  • To: Eric Bohm <ebohm AT illinois.edu>
  • Cc: Scott Biersdorff <scottb AT cs.uoregon.edu>, charm AT cs.uiuc.edu
  • Subject: Re: [charm] perf data in charm++
  • Date: Thu, 28 Feb 2013 12:56:31 -0800
  • List-archive: <http://lists.cs.uiuc.edu/pipermail/charm/>
  • List-id: CHARM parallel programming system <charm.cs.uiuc.edu>

Eric & Laxmikant,

Thank you very much for responding -- this really helps me.
The app I'm looking at (which is just the UTS benchmark) already
had a target with -tracemode projects in the Makefile -- I just didn't
realize it was related to perf data.

I had already been exchanging emails with Scott and he suggested I ask the
Charm++ list
a question.

Noel

On Feb 28, 2013, at 10:41 AM, Eric Bohm wrote:

> There are a wide variety of ways which Charm++ applications might make use
> of threads. The current TAU interface is somewhat limited in how well it
> identifies them.
>
> The most common case is in an smp based build where pthreads are launched
> at startup and pinned 1:1 to cores (or SMTs) as governed by the use of
> command line arguments. They then act as the computational environment for
> the Charm++ message driven paradigm without exposing pthread semantics to
> the user.
>
> A slightly less common case uses Charm++ lightweight threads (not pthreads)
> at a ratio higher than the number of hardware execution units. AMPI is
> the typical venue for this, where each lightweight thread holds an MPI
> rank. Again, those threads are typically all launched at startup rather
> than being dynamically created/destroyed. The lightweight thread scheme can
> also be used directly via the [threaded] semantics of charm++, an example
> of this can be found in the ChaNGa application. In those cases, the
> Projections tool
> http://charm.cs.illinois.edu/manuals/html/projections/manual.html is
> generally useful for performance analysis.
>
> It is also possible to mix OpenMP instructions with Charm++. However, in
> that case the performance of those threads is controlled by the OMP
> infrastructure rather than Charm++.
>
> I have also cc'd Scott Biersdorff on this because I believe he is the most
> familiar with the Charm TAU interface.
>
> On 02/28/2013 12:07 PM, Noel Keen wrote:
>> Hello,
>>
>> I'm trying to get some perf data on a charm++ app. Looking for the number
>> of threads created and the expense of the creation/deletion, etc. I'm
>> trying to build charm++ with TAU on a Cray XT with limited success.
>> But if someone knows anything about getting this type of perf data,
>> let me know. Thanks
>>
>> Noel
>> _______________________________________________
>> charm mailing list
>> charm AT cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/charm
>
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