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<p class="MsoNormal">Dear people<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’d had terrible performance of my application which is intended to run on IO nodes, so I’ve been poking around to try to find out what might be wrong.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Today I compiled a simple stream memory writing test from <a href="http://www.cs.virginia.edu/stream/FTP/Code/">
http://www.cs.virginia.edu/stream/FTP/Code/</a> <o:p></o:p></p>
<p class="MsoNormal">I’ve run it using openmp threads up to 60, (because for reasons I don’t understand, the IO node only shows 15*4 threads)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The results for bgclang seem to echo what I’ve been finding with my code. I have not tested my stuff fully with gcc as I only just got that installed recently.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Any advice on what I might try to improve the bgclang numbers? in some cases gcc looks 2x better.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Note that my program doesn’t use openmp so I don’t directly care much about this particular example, but the trend mirrors what I’m seeing with HPX threads<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">thanks<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">JB<o:p></o:p></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">using bgclang version 20140309<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">export OMP_NUM_THREADS=1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Function Best Rate MB/s Avg time Min time Max time<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Copy: 659.5 0.242635 0.242601 0.242724<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Scale: 536.2 0.298403 0.298376 0.298535<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Add: 828.5 0.289701 0.289669 0.289839<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Triad: 711.8 0.337206 0.337151 0.337325<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">export OMP_NUM_THREADS=2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Function Best Rate MB/s Avg time Min time Max time<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Copy: 1318.8 0.121335 0.121322 0.121360<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Scale: 1072.5 0.149223 0.149185 0.149375<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Add: 1657.2 0.144868 0.144823 0.145036<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Triad: 1423.8 0.168611 0.168565 0.168755<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">export OMP_NUM_THREADS=4<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Function Best Rate MB/s Avg time Min time Max time<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Copy: 2636.4 0.060729 0.060688 0.060919<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Scale: 2236.9 0.071580 0.071529 0.071774<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Add: 3311.2 0.072555 0.072482 0.072750<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Triad: 2845.6 0.084426 0.084341 0.084540<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">export OMP_NUM_THREADS=8<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Function Best Rate MB/s Avg time Min time Max time<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Copy: 5265.6 0.030446 0.030386 0.030614<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Scale: 4468.1 0.035848 0.035809 0.036030<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Add: 6611.9 0.036341 0.036298 0.036526<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Triad: 5684.9 0.042258 0.042217 0.042420
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">export OMP_NUM_THREADS=16<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Function Best Rate MB/s Avg time Min time Max time<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Copy: 9390.8 0.018977 0.017038 0.025704<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Scale: 7688.2 0.021786 0.020811 0.029255<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Add: 11985.7 0.020990 0.020024 0.028394<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Triad: 10875.0 0.023131 0.022069 0.031470
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">export OMP_NUM_THREADS=32<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Function Best Rate MB/s Avg time Min time Max time<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Copy: 15556.4 0.011463 0.010285 0.012906<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Scale: 13361.1 0.013228 0.011975 0.014883<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Add: 20438.0 0.012872 0.011743 0.014259<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Triad: 18047.8 0.014270 0.013298 0.016016
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">export OMP_NUM_THREADS=60<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Function Best Rate MB/s Avg time Min time Max time<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Copy: 11472.0 0.016570 0.013947 0.022287<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Scale: 10145.1 0.019031 0.015771 0.028346<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Add: 15317.9 0.018322 0.015668 0.025756<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Triad: 14106.8 0.018959 0.017013 0.025986
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">using GCC 4.8.2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">export OMP_NUM_THREADS=1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Function Best Rate MB/s Avg time Min time Max time<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Copy: 3534.4 0.045289 0.045270 0.045306<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Scale: 1318.8 0.121390 0.121325 0.121632<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Add: 1899.0 0.126403 0.126384 0.126428<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Triad: 1910.3 0.125667 0.125637 0.125724<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">export OMP_NUM_THREADS=2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Function Best Rate MB/s Avg time Min time Max time<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Copy: 7053.2 0.022716 0.022685 0.022744<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Scale: 2613.9 0.061247 0.061211 0.061278<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Add: 3794.3 0.063271 0.063252 0.063292<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Triad: 3794.4 0.063288 0.063251 0.063449<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">export OMP_NUM_THREADS=4<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Function Best Rate MB/s Avg time Min time Max time<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Copy: 13999.4 0.011470 0.011429 0.011494<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Scale: 5218.5 0.030683 0.030660 0.030729<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Add: 7585.3 0.031647 0.031640 0.031681<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Triad: 7583.4 0.031663 0.031648 0.031690<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">export OMP_NUM_THREADS=8<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Function Best Rate MB/s Avg time Min time Max time<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Copy: 25910.8 0.006205 0.006175 0.006233<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Scale: 10432.9 0.015373 0.015336 0.015484<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Add: 15130.5 0.015922 0.015862 0.016092<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Triad: 15116.2 0.015971 0.015877 0.016139<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">export OMP_NUM_THREADS=16<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Function Best Rate MB/s Avg time Min time Max time<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Copy: 28433.5 0.005643 0.005627 0.005665<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Scale: 20547.1 0.007831 0.007787 0.007860<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Add: 27006.3 0.008922 0.008887 0.008948<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Triad: 27758.5 0.008658 0.008646 0.008672<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">export OMP_NUM_THREADS=32<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Function Best Rate MB/s Avg time Min time Max time<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Copy: 28368.6 0.005673 0.005640 0.005742<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Scale: 26302.8 0.006115 0.006083 0.006175<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Add: 27164.4 0.008878 0.008835 0.008960<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Triad: 27691.3 0.008702 0.008667 0.008744<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">export OMP_NUM_THREADS=60<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Function Best Rate MB/s Avg time Min time Max time<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Copy: 25715.2 0.008484 0.006222 0.012176<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Scale: 22472.2 0.012979 0.007120 0.021724<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Add: 25319.6 0.014178 0.009479 0.023234<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">Triad: 25591.9 0.013839 0.009378 0.023146<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">-------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";mso-fareast-language:EN-GB">--
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";mso-fareast-language:EN-GB">John Biddiscombe, email:biddisco @.at.@ cscs.ch<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";mso-fareast-language:EN-GB"><a href="http://www.cscs.ch/"><span style="color:windowtext">http://www.cscs.ch/</span></a><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";mso-fareast-language:EN-GB">CSCS, Swiss National Supercomputing Centre | Tel: +41 (91) 610.82.07<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="IT-CH" style="font-size:10.0pt;font-family:"Courier New";mso-fareast-language:EN-GB">Via Trevano 131, 6900 Lugano, Switzerland | Fax: +41 (91) 610.82.82<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="IT-CH"><o:p> </o:p></span></p>
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