<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Dear Carlo,<div><br></div><div><div>On Jul 30, 2012, at 6:14 PM, Carlo Cavazzoni wrote:</div><blockquote type="cite"><div>Number of | Number of | sec/ | OpenMP | command line<br>real cores | virtual cores | iteration | threads | parameters<br> 4096 | 8192 | 231 | 4 | -nbgrp 2 -ntg 4 <br>-ndiag 256<br> 8192 | 16384 | 160 | 4 | -nbgrp 4 -ntg 4 <br>-ndiag 1024<br>16384 | 32768 | 131 | 4 | -nbgrp 4 -ntg 4 <br>-ndiag 1024<br>32768 | 65536 | 86 | 4 | -nbgrp 8 -ntg 4 <br>-ndiag 2048</div></blockquote><br></div><div>benchmarking GPU PWscf on medium/big systems (>500 atoms) I found in the PW code several spots where adding OpenMP will improve the performance (of those sections) of a factor (at least) 2. I haven't committed anything yet. However, it is interesting to evaluate the OpenMP efficiency/scalability. I see you did tests using 4 OpenMP (I assume 8 MPI per A2 chip, 2 OpenMP thread per physical core, 2 GByte per RAM each task. correct?). What about 8 OpenMP threads? or 16? Is it worth to go over 4 OpenMP threads?<div><div><br></div><div><br><blockquote type="cite"><div>(Volunteer are welcome too!)<br></div></blockquote></div><div><br></div><div>I am more than happy to help (-:</div><div><br></div><div>F.</div><br><div apple-content-edited="true">
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-webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">-- <br>Mr. Filippo SPIGA (穗安駒), HPC and GPU Technologist <spiga.filippo_at_gmail.com></div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">website: <a href="http://filippospiga.me">http://filippospiga.me</a> ~ skype: filippo.spiga<br><br>«Nobody will drive us out of Cantor's paradise.» ~ David Hilbert</div></span></div></span></div></span></div></span></div></span></div></span></div></span></div></span></div></span></div></span></div></span></div></span></div></span></span>
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