<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>+1 on disabling THP</div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">Charlie </div><div><br>On Oct 29, 2016, at 10:07 AM, Vitaly Davidovich <<a href="mailto:vitalyd@gmail.com">vitalyd@gmail.com</a>> wrote:<br><br></div><blockquote type="cite"><div>David,<div><br></div><div>Ask them to turn off THP - it's a known source of large latency due to the kernel doing page defragmentation; your app takes a page fault, and boom - the kernel may start doing defragmentation to make a huge page available. You can search online for THP issues. The symptoms are similar to yours - very high sys time.</div><div><br></div><div>If they turn it off and still get same lengthy parnew pauses, then it's clearly something else but at least we'll eliminate THP as the culprit.<span></span><br><br>On Saturday, October 29, 2016, David Ely <<a href="mailto:david.ely@unboundid.com">david.ely@unboundid.com</a>> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><font face="arial, helvetica, sans-serif">Thank you for the response. Yes. meminfo (see full output below) shows ~80GB of AnonHugePages, which is pretty close to the size of the JVM (full output below). Looking back through previous information that we have from this customer, transparent huge pages have been turned on for years</font><span style="font-family:arial,helvetica,sans-serif">. We've asked them for anything else that might have changed in this environment.</span></div><div><span style="font-family:arial,helvetica,sans-serif"><br></span></div><div><span style="font-family:arial,helvetica,sans-serif">Are there any other JVM options that we could enable that would shed light on what's going on within the ParNew? Would </span><span style="font-family:arial,helvetica,sans-serif">-XX:+PrintTLAB </span><span style="font-family:arial,helvetica,sans-serif">-XX:+<wbr>PrintPLAB </span><span style="font-family:arial,helvetica,sans-serif">-XX:<wbr>PrintFLSStatistics=1 show anything useful?</span></div><div><font face="arial, helvetica, sans-serif"><div><br></div><div>David</div><div><br></div><div><br></div></font></div><div><font face="monospace, monospace">MemTotal: 264396572 kB</font></div><div><font face="monospace, monospace">MemFree: 2401576 kB</font></div><div><font face="monospace, monospace">Buffers: 381564 kB</font></div><div><font face="monospace, monospace">Cached: 172673120 kB</font></div><div><font face="monospace, monospace">SwapCached: 0 kB</font></div><div><font face="monospace, monospace">Active: 163439836 kB</font></div><div><font face="monospace, monospace">Inactive: 90737452 kB</font></div><div><font face="monospace, monospace">Active(anon): 76910848 kB</font></div><div><font face="monospace, monospace">Inactive(anon): 4212580 kB</font></div><div><font face="monospace, monospace">Active(file): 86528988 kB</font></div><div><font face="monospace, monospace">Inactive(file): 86524872 kB</font></div><div><font face="monospace, monospace">Unevictable: 0 kB</font></div><div><font face="monospace, monospace">Mlocked: 0 kB</font></div><div><font face="monospace, monospace">SwapTotal: 16236540 kB</font></div><div><font face="monospace, monospace">SwapFree: 16236540 kB</font></div><div><font face="monospace, monospace">Dirty: 14552 kB</font></div><div><font face="monospace, monospace">Writeback: 0 kB</font></div><div><font face="monospace, monospace">AnonPages: 81111768 kB</font></div><div><font face="monospace, monospace">Mapped: 31312 kB</font></div><div><font face="monospace, monospace">Shmem: 212 kB</font></div><div><font face="monospace, monospace">Slab: 6078732 kB</font></div><div><font face="monospace, monospace">SReclaimable: 5956052 kB</font></div><div><font face="monospace, monospace">SUnreclaim: 122680 kB</font></div><div><font face="monospace, monospace">KernelStack: 41296 kB</font></div><div><font face="monospace, monospace">PageTables: 171324 kB</font></div><div><font face="monospace, monospace">NFS_Unstable: 0 kB</font></div><div><font face="monospace, monospace">Bounce: 0 kB</font></div><div><font face="monospace, monospace">WritebackTmp: 0 kB</font></div><div><font face="monospace, monospace">CommitLimit: 148434824 kB</font></div><div><font face="monospace, monospace">Committed_AS: 93124984 kB</font></div><div><font face="monospace, monospace">VmallocTotal: 34359738367 kB</font></div><div><font face="monospace, monospace">VmallocUsed: 686780 kB</font></div><div><font face="monospace, monospace">VmallocChunk: 34225639420 kB</font></div><div><font face="monospace, monospace">HardwareCorrupted: 0 kB</font></div><div><font face="monospace, monospace"><b>AnonHugePages: 80519168 kB</b></font></div><div><font face="monospace, monospace">HugePages_Total: 0</font></div><div><font face="monospace, monospace">HugePages_Free: 0</font></div><div><font face="monospace, monospace">HugePages_Rsvd: 0</font></div><div><font face="monospace, monospace">HugePages_Surp: 0</font></div><div><font face="monospace, monospace">Hugepagesize: 2048 kB</font></div><div><font face="monospace, monospace">DirectMap4k: 5132 kB</font></div><div><font face="monospace, monospace">DirectMap2M: 1957888 kB</font></div><div><font face="monospace, monospace">DirectMap1G: 266338304 kB</font></div><div><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Oct 28, 2016 at 8:04 PM, Vitaly Davidovich <span dir="ltr"><<a href="javascript:_e(%7B%7D,'cvml','vitalyd@gmail.com');" target="_blank">vitalyd@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div><br><br>On Friday, October 28, 2016, David Ely <<a href="javascript:_e(%7B%7D,'cvml','david.ely@unboundid.com');" target="_blank">david.ely@unboundid.com</a>> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>While typical ParNew GC times are 50ms, our application is occasionally hitting ParNew times that are over 15 seconds for one of our customers, and we have no idea why. Looking at the full GC log file:</div><div><br></div><div>382250 ParNew GCs are < 1 second<br></div><div>9303 are 100ms to 1 second<br></div><div>1267 are 1 second to 2 seconds<br></div><div>99 are 2 seconds to 10 seconds<br></div><div>24 are > 10 seconds, 48 seconds being the max<br></div><div><br></div><div>The long ones are somewhat bursty as you can see from looking at the line numbers in the GC log:</div><div><br></div><div><div><div>$ egrep -n '(ParNew.*real=[1-9][0-9]\)' gc.log.0 </div><div><br></div><div><div>12300:2016-10-21T01:03:20.380+<wbr>0000: 20278.069: [GC2016-10-21T01:03:20.380+000<wbr>0: 20278.070: [ParNew: 1697741K->10024K(1887488K), 16.9913450 secs] 33979542K->32817239K(84724992K<wbr>), 16.9921050 secs] [Times: user=541.32 sys=14.37, real=16.99 secs] </div><div>43730:2016-10-21T14:12:25.050+<wbr>0000: 67622.740: [GC2016-10-21T14:12:25.051+000<wbr>0: 67622.740: [ParNew: 1728194K->33817K(1887488K), 12.7508470 secs] 49737924K->48320707K(84724992K<wbr>), 12.7517840 secs] [Times: user=405.89 sys=11.05, real=12.75 secs] </div><div>44079:2016-10-21T14:18:55.172+<wbr>0000: 68012.862: [GC2016-10-21T14:18:55.173+000<wbr>0: 68012.862: [ParNew: 1698371K->26958K(1887488K), 12.7384460 secs] 50339815K->48930730K(84724992K<wbr>), 12.7392360 secs] [Times: user=406.58 sys=11.29, real=12.73 secs] </div><div>50151:2016-10-21T17:10:14.471+<wbr>0000: 78292.160: [GC2016-10-21T17:10:14.471+000<wbr>0: 78292.161: [ParNew: 1713813K->40968K(1887488K), 18.6593320 secs] 49366906K->47959129K(84724992K<wbr>), 18.6602550 secs] [Times: user=590.03 sys=17.45, real=18.66 secs] </div><div>56073:2016-10-21T19:59:36.847+<wbr>0000: 88454.536: [GC2016-10-21T19:59:36.847+000<wbr>0: 88454.537: [ParNew: 1685720K->20763K(1887488K), 16.0840200 secs] 50704025K->49302131K(84724992K<wbr>), 16.0848810 secs] [Times: user=487.00 sys=16.84, real=16.09 secs] </div><div>78987:2016-10-22T05:49:25.623+<wbr>0000: 123843.312: [GC2016-10-22T05:49:25.623+000<wbr>0: 123843.313: [ParNew: 1709771K->22678K(1887488K), 10.9933380 secs] 43323834K->41914203K(84724992K<wbr>), 10.9943060 secs] [Times: user=349.67 sys=9.84, real=10.99 secs] </div><div>79104:2016-10-22T05:59:26.382+<wbr>0000: 124444.071: [GC2016-10-22T05:59:26.382+000<wbr>0: 124444.072: [ParNew: 1697024K->22260K(1887488K), 11.5490390 secs] 44558499K->43145880K(84724992K<wbr>), 11.5499650 secs] [Times: user=367.73 sys=10.01, real=11.55 secs] </div><div>79504:2016-10-22T06:09:36.983+<wbr>0000: 125054.672: [GC2016-10-22T06:09:36.984+000<wbr>0: 125054.673: [ParNew: 1688112K->4769K(1887488K), 14.1528810 secs] 46684947K->45263748K(84724992K<wbr>), 14.1539860 secs] [Times: user=452.28 sys=12.71, real=14.15 secs] </div><div>79772:2016-10-22T06:30:36.130+<wbr>0000: 126313.819: [GC2016-10-22T06:30:36.130+000<wbr>0: 126313.820: [ParNew: 1725520K->35893K(1887488K), 14.4479670 secs] 48989739K->47563879K(84724992K<wbr>), 14.4488810 secs] [Times: user=461.60 sys=13.04, real=14.45 secs] </div><div>80087:2016-10-22T06:37:07.202+<wbr>0000: 126704.891: [GC2016-10-22T06:37:07.202+000<wbr>0: 126704.892: [ParNew: 1698021K->23440K(1887488K), 15.7039920 secs] 50517163K->49105987K(84724992K<wbr>), 15.7050040 secs] [Times: user=497.65 sys=14.75, real=15.70 secs] </div><div>89969:2016-10-22T13:54:27.978+<wbr>0000: 152945.667: [GC2016-10-22T13:54:27.978+000<wbr>0: 152945.668: [ParNew: 1834914K->15978K(1887488K), 11.5637150 secs] 48716340K->47307673K(84724992K<wbr>), 11.5645440 secs] [Times: user=367.77 sys=10.01, real=11.57 secs] </div><div>90200:2016-10-22T14:05:02.717+<wbr>0000: 153580.407: [GC2016-10-22T14:05:02.718+000<wbr>0: 153580.407: [ParNew: 1684626K->7078K(1887488K), 17.3424650 secs] 50361539K->48947648K(84724992K<wbr>), 17.3433490 secs] [Times: user=554.39 sys=15.81, real=17.34 secs] </div><div>90299:2016-10-22T14:14:30.521+<wbr>0000: 154148.210: [GC2016-10-22T14:14:30.521+000<wbr>0: 154148.211: [ParNew: 1690850K->6078K(1887488K), 13.1699350 secs] 51455784K->50033156K(84724992K<wbr>), 13.1708900 secs] [Times: user=419.55 sys=11.54, real=13.17 secs] </div><div>261329:2016-10-26T00:06:44.499<wbr>+0000: 448882.189: [GC2016-10-26T00:06:44.500+000<wbr>0: 448882.189: [ParNew: 1705614K->22224K(1887488K), 17.5831730 secs] 40683698K->39525817K(84724992K<wbr>), 17.5843270 secs] [Times: user=561.85 sys=14.79, real=17.58 secs] </div><div>261935:2016-10-26T00:13:34.277<wbr>+0000: 449291.967: [GC2016-10-26T00:13:34.278+000<wbr>0: 449291.967: [ParNew: 1690085K->26707K(1887488K), 13.9331790 secs] 43792178K->42655000K(84724992K<wbr>), 13.9340780 secs] [Times: user=446.36 sys=11.45, real=13.93 secs] </div><div>262143:2016-10-26T00:20:09.397<wbr>+0000: 449687.087: [GC2016-10-26T00:20:09.398+000<wbr>0: 449687.087: [ParNew: 1696593K->27078K(1887488K), 40.3344500 secs] 45588644K->44444949K(84724992K<wbr>), 40.3355430 secs] [Times: user=1248.15 sys=43.07, real=40.33 secs] </div><div>262275:2016-10-26T00:27:02.196<wbr>+0000: 450099.886: [GC2016-10-26T00:27:02.197+000<wbr>0: 450099.886: [ParNew: 1683406K->17853K(1887488K), 17.7472360 secs] 46908499K->45506131K(84724992K<wbr>), 17.7482260 secs] [Times: user=567.03 sys=16.10, real=17.75 secs] </div><div>262282:2016-10-26T00:27:29.448<wbr>+0000: 450127.138: [GC2016-10-26T00:27:29.449+000<wbr>0: 450127.138: [ParNew: 1687737K->10499K(1887488K), 35.4934000 secs] 47195678K->46044477K(84724992K<wbr>), 35.4943230 secs] [Times: user=1131.34 sys=31.87, real=35.49 secs] </div><div>262631:2016-10-26T00:34:17.632<wbr>+0000: 450535.321: [GC2016-10-26T00:34:17.632+000<wbr>0: 450535.321: [ParNew: 1687590K->10226K(1887488K), 21.4043600 secs] 49431427K->48018504K(84724992K<wbr>), 21.4052230 secs] [Times: user=682.50 sys=19.46, real=21.41 secs] </div><div>262844:2016-10-26T00:41:08.118<wbr>+0000: 450945.808: [GC2016-10-26T00:41:08.119+000<wbr>0: 450945.808: [ParNew: 1692928K->11302K(1887488K), 48.2899260 secs] 51073216K->49915878K(84724992K<wbr>), 48.2909550 secs] [Times: user=1493.17 sys=53.55, real=48.28 secs] </div><div>345421:2016-10-27T04:17:59.617<wbr>+0000: 550357.306: [GC2016-10-27T04:17:59.618+000<wbr>0: 550357.307: [ParNew: 1695052K->22991K(1887488K), 33.8707510 secs] 46334738K->45187822K(84724992K<wbr>), 33.8718980 secs] [Times: user=1081.31 sys=30.59, real=33.86 secs] </div><div>345510:2016-10-27T04:24:11.721<wbr>+0000: 550729.411: [GC2016-10-27T04:24:11.722+000<wbr>0: 550729.411: [ParNew: 1705080K->20401K(1887488K), 18.9795540 secs] 47388073K->45965537K(84724992K<wbr>), 18.9805410 secs] [Times: user=606.94 sys=17.25, real=18.98 secs] </div><div>345514:2016-10-27T04:24:36.695<wbr>+0000: 550754.385: [GC2016-10-27T04:24:36.696+000<wbr>0: 550754.385: [ParNew: 1707810K->32640K(1887488K), 30.9728200 secs] 47656489K->46506725K(84724992K<wbr>), 30.9737300 secs] [Times: user=917.67 sys=33.07, real=30.97 secs] </div><div>345777:2016-10-27T04:31:30.102<wbr>+0000: 551167.791: [GC2016-10-27T04:31:30.102+000<wbr>0: 551167.791: [ParNew: 1704518K->30860K(1887488K), 38.0976720 secs] 49570144K->48422333K(84724992K<wbr>), 38.0984950 secs] [Times: user=1215.89 sys=34.79, real=38.09 secs] </div></div><div><br></div><div>Context around a single instance is fairly normal:</div><div><br></div><div><div>345773-2016-10-27T04:31:28.032<wbr>+0000: 551165.721: [GC2016-10-27T04:31:28.033+000<wbr>0: 551165.722: [ParNew: 1685858K->8851K(1887488K), 0.0480250 secs] 49545909K->47870050K(84724992K<wbr>), 0.0490200 secs] [Times: user=1.47 sys=0.02, real=0.05 secs] </div><div>345774-2016-10-27T04:31:28.635<wbr>+0000: 551166.324: [GC2016-10-27T04:31:28.636+000<wbr>0: 551166.325: [ParNew: 1686675K->10456K(1887488K), 0.0463570 secs] 49547874K->47872545K(84724992K<wbr>), 0.0473410 secs] [Times: user=1.41 sys=0.04, real=0.05 secs] </div><div>345775-2016-10-27T04:31:29.205<wbr>+0000: 551166.894: [GC2016-10-27T04:31:29.205+000<wbr>0: 551166.894: [ParNew: 1688280K->12733K(1887488K), 0.0487100 secs] 49550369K->47876404K(84724992K<wbr>), 0.0496310 secs] [Times: user=1.47 sys=0.04, real=0.05 secs] </div><div>345776-2016-10-27T04:31:29.798<wbr>+0000: 551167.487: [GC2016-10-27T04:31:29.798+000<wbr>0: 551167.488: [ParNew: 1690557K->26694K(1887488K), 0.0471170 secs] 49554228K->47892320K(84724992K<wbr>), 0.0481180 secs] [Times: user=1.40 sys=0.02, real=0.05 secs] </div><div>345777:2016-10-27T04:31:30.102<wbr>+0000: 551167.791: [GC2016-10-27T04:31:30.102+000<wbr>0: 551167.791: [ParNew: 1704518K->30860K(1887488K), 38.0976720 secs] 49570144K->48422333K(84724992K<wbr>), 38.0984950 secs] [Times: user=1215.89 sys=34.79, real=38.09 secs] </div><div>345778-2016-10-27T04:32:08.449<wbr>+0000: 551206.139: [GC2016-10-27T04:32:08.450+000<wbr>0: 551206.139: [ParNew: 1708684K->122033K(1887488K), 0.0664280 secs] 50100157K->48528020K(84724992K<wbr>), 0.0672860 secs] [Times: user=1.60 sys=0.05, real=0.07 secs] </div><div>345779-2016-10-27T04:32:09.090<wbr>+0000: 551206.779: [GC2016-10-27T04:32:09.091+000<wbr>0: 551206.780: [ParNew: 1799857K->42169K(1887488K), 0.0688910 secs] 50205844K->48541030K(84724992K<wbr>), 0.0696110 secs] [Times: user=1.70 sys=0.03, real=0.07 secs] </div><div>345780-2016-10-27T04:32:09.802<wbr>+0000: 551207.491: [GC2016-10-27T04:32:09.802+000<wbr>0: 551207.491: [ParNew: 1719993K->43790K(1887488K), 0.0508540 secs] 50218854K->48542651K(84724992K<wbr>), 0.0516000 secs] [Times: user=1.54 sys=0.03, real=0.05 secs] </div><div>345781-2016-10-27T04:32:10.536<wbr>+0000: 551208.226: [GC2016-10-27T04:32:10.537+000<wbr>0: 551208.226: [ParNew: 1721614K->30389K(1887488K), 0.0668100 secs] 50220475K->48545932K(84724992K<wbr>), 0.0675470 secs] [Times: user=1.81 sys=0.03, real=0.06 secs] </div><div>345782-2016-10-27T04:32:11.137<wbr>+0000: 551208.826: [GC2016-10-27T04:32:11.137+000<wbr>0: 551208.826: [ParNew: 1708213K->18631K(1887488K), 0.0632570 secs] 50223756K->48540797K(84724992K<wbr>), 0.0639650 secs] [Times: user=1.95 sys=0.01, real=0.06 secs] </div><div>345783-2016-10-27T04:32:11.642<wbr>+0000: 551209.332: [GC2016-10-27T04:32:11.643+000<wbr>0: 551209.332: [ParNew: 1696455K->19415K(1887488K), 0.0509260 secs] 50218621K->48545033K(84724992K<wbr>), 0.0516780 secs] [Times: user=1.55 sys=0.03, real=0.05 secs] </div></div><div><br></div><div>Since the user times are high as well, I don't think this could be swapping.<br></div></div></div></div></blockquote></div></div><div>Can you ask the customer if they're using transparent hugepages (THP)? </div><div><div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><br></div><div>Here are the hard-earned set of JVM arguments that we're using:</div><div><br></div><div><div><div><div>-d64 -server -Xmx81g -Xms81g -XX:MaxNewSize=2g \</div><div> -XX:NewSize=2g -XX:+UseConcMarkSweepGC -XX:+CMSConcurrentMTEnabled \</div><div> -XX:+CMSParallelRemarkEnabled -XX:+CMSParallelSurvivorRemark<wbr>Enabled \</div><div> -XX:+CMSScavengeBeforeRemark -XX:RefDiscoveryPolicy=1 \</div><div> -XX:ParallelCMSThreads=12 -XX:CMSMaxAbortablePrecleanTim<wbr>e=3600000 \</div><div> -XX:CMSInitiatingOccupancyFrac<wbr>tion=60 -XX:+UseParNewGC -XX:+UseBiasedLocking \</div><div> -XX:MaxTenuringThreshold=2 -XX:+UseCompressedOops -XX:PermSize=256M \</div><div> -XX:MaxPermSize=256M -XX:+HeapDumpOnOutOfMemoryErro<wbr>r \</div><div> -XX:+UseCMSInitiatingOccupancy<wbr>Only -XX:+UseMembar -XX:+UseLargePages \</div><div> -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintCommandLineFlags \</div><div> -XX:+UseGCLogFileRotation \</div><div> -XX:NumberOfGCLogFiles=3 -XX:GCLogFileSize=100m \</div><div> -Xloggc:${INSTANCE_ROOT}/logs/<wbr>jvm/gc.log</div><div><br></div></div></div></div><div>This is on Linux with Java 1.7.0_72.</div><div><br></div><div>Does this look familiar to anyone? Alternatively, are there some more JVM options that we could include to get more information? </div><div><br></div><div>One of the first things that we'll try is to move to a later JVM, but it will be easier to get the customer to do that if we can point to a specific issue that has been addressed.</div><div><br></div><div>Thanks for your help.</div><div><br></div><div>David</div></div>
</blockquote><br><br></div></div><span><font color="#888888">-- <br>Sent from my phone<br>
</font></span></blockquote></div><br></div></div>
</blockquote></div><br><br>-- <br>Sent from my phone<br>
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