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<p>Hi Phil</p>
<p>totally agree.</p>
<p>I really appreciated your support very much.</p>
<p>P.S is it possible to undestand at a more detailed level all the
parser output?</p>
<p>I still have some problem while trying to relate some of those
values. For example, running MPIIO version, the following appears:</p>
<p>1) MPIIO_F_WRITE_TIME 103.772865</p>
<p>2)MPIIO_F_MAX_WRITE_TIME 3.107764 <br>
</p>
<p>3)MPIIO_F_WRITE_START_TIMESTAMP 22.217328 <br>
</p>
<p> 4) MPIIO_F_CLOSE_START_TIMESTAMP 25.707373 <br>
</p>
<p>so, is difficult to relate one with two or one with three, four
values.</p>
<p>thanks again</p>
<p>Piero<br>
</p>
<div class="moz-cite-prefix">Il 13/02/2020 14:18, Carns, Philip H.
ha scritto:<br>
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cite="mid:BN8PR09MB3620EC899B5AB391D47FDAF6F71A0@BN8PR09MB3620.namprd09.prod.outlook.com">
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255, 255);">
Thanks Piero. I agree, but from a practical point of view, I
don't see many options for improving Darshan's handling of this
particular scenario. If something in the Fortran runtime is
impacting perceived I/O performance, then the only way to
observe it would be to wrap/instrument at the Fortran level
rather than at the system library (libc) level. Otherwise
Darshan can't tell the difference between the Fortran calls
being slow or the Fortran calls being fast with the app doing
something else in between calls.<br>
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<br>
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We've been reluctant to pursue that approach (we've hit cases
before where instrumenting the Fortran level would have been
helpful) because of the development/maintenance cost, in part
because there is so much variety in the Fortran compiler world,
and in part because our team simply doesn't have a lot of
Fortran expertise.<br>
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<br>
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That said, we would entertain a contribution along these lines
<span>��</span> Something like that could be enabled as a
compile-time option.</div>
<br>
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<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
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255, 255);">
The good news (as you've seen with the MPI tests from benchio)
is that what you are describing isn't really a problem for the
MPI-IO interface. Most of the existing MPI-IO Fortran bindings
map almost directly to the underlying C MPI-IO bindings, meaning
that what we measure at that level should be a pretty accurate
indication of what's going on at the Fortran level. The
scenario you have hit is an issue because the Fortran I/O calls
likely have more logic that actually resides in the Fortran
runtime itself.<br>
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thanks,</div>
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255, 255);">
-Phil<br>
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