<div dir="ltr"><div>Hi Pedro,</div><div><br></div><div>I suspect your per-block zone counts are too low to see benefits of adding more procs at this point. The details will depend on your specific problem and hardware of course, but when I've done strong scaling studies I've found (rapidly) diminishing returns to adding more procs once I fall below about ~1000 zones per proc. I think this is what you're seeing in your nxb=nxy=16 and nxb=nxy=28 cases. If your scaling study continues up to several thousand zones per proc, I bet you'll see more of the expected behavior.</div><div><br></div><div>Hope this helps!</div><div>Lee</div><div><br></div><div> ________________</div><div>Leland Ellison PhD<div>Computational Physicist</div><div><a href="https://www.linkedin.com/in/clelandellison/" target="_blank">https://www.linkedin.com/in/clelandellison/</a><br></div><div><a href="https://scholar.google.com/citations?user=1rfcVWgAAAAJ" target="_blank">https://scholar.google.com/citations?user=1rfcVWgAAAAJ</a></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Apr 5, 2023 at 6:46 AM pedro romero <<a href="mailto:pedro.romero@greentownsbyfusion.com">pedro.romero@greentownsbyfusion.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="msg-4342692014054491247">
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<p class="MsoNormal"><span>Hi Paco,<u></u><u></u></span></p>
<p class="MsoNormal"><span><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">As far as I know, using uniform grid fixes the number of blocks as one per processor. Am I wrong? Do you mean to fix nxb and nyb while varying the cores?<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
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<p class="MsoNormal"><b>De:</b> Francisco Holguin <<a href="mailto:opaco@umich.edu" target="_blank">opaco@umich.edu</a>> <br>
<b>Enviado el:</b> miércoles, 5 de abril de 2023 15:17<br>
<b>Para:</b> pedro romero <<a href="mailto:pedro.romero@greentownsbyfusion.com" target="_blank">pedro.romero@greentownsbyfusion.com</a>><br>
<b>CC:</b> <a href="mailto:flash-users@flash.rochester.edu" target="_blank">flash-users@flash.rochester.edu</a><br>
<b>Asunto:</b> Re: [FLASH-USERS] Scaling problems<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">Hi Pedro,<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">What if you just fix the number of blocks, and vary the cores?<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">-Paco<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">On Wed, Apr 5, 2023 at 5:13 AM pedro romero <<a href="mailto:pedro.romero@greentownsbyfusion.com" target="_blank">pedro.romero@greentownsbyfusion.com</a>> wrote:<u></u><u></u></p>
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<p class="MsoNormal">Hi all,<u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">I am trying to scale up on computational resources and I came across a few issues. First of all, I am running the same +ug example (a modification of 2D Zpinch
template) varying the number of cores, nxb and nyb but it shows no speed up as the number of cores increase (I am tuning Iprocs, Jprocs, nxb and nyb to always get an approximately equal grid).
</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">Furthermore, at a certain number of cores the program execution interrupts, and I get a SIGBUS error (which I attach to this message). Am I missing something?
Is there any additional thing to consider?</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">I will also attach the log file of one successful run using 36 cores and nxb=nyb=16 (which shows little or no speed up in comparison to a run on 12 cores and
nxb=nyb=28). Thank you in advance for any help.</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">Pedro</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
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