Looking at that profile: Misc. blocking socket activity, not actual CPU work: 1 5.24% 5.24% 67781 300447 java.net.PlainSocketImpl.socketAccept 2 5.24% 10.49% 67775 300515 java.net.PlainSocketImpl.socketAccept 3 5.24% 15.73% 67773 300567 java.net.PlainSocketImpl.socketAccept 4 5.24% 20.97% 67683 301396 sun.nio.ch.ServerSocketChannelImpl.accept0 5 5.23% 26.20% 67582 301395 sun.nio.ch.EPollArrayWrapper.epollWait 6 5.23% 31.42% 67529 301519 sun.nio.ch.EPollArrayWrapper.epollWait 7 5.13% 36.55% 66297 302447 sun.nio.ch.EPollArrayWrapper.epollWait 8 3.95% 40.51% 51071 302446 sun.nio.ch.EPollArrayWrapper.epollWait 9 3.65% 44.16% 47234 303479 sun.nio.ch.EPollArrayWrapper.epollWait 10 3.64% 47.80% 47019 302444 sun.nio.ch.EPollArrayWrapper.epollWait 11 3.62% 51.42% 46768 302445 sun.nio.ch.EPollArrayWrapper.epollWait 12 3.27% 54.69% 42237 303475 sun.nio.ch.EPollArrayWrapper.epollWait 13 3.16% 57.85% 40892 303476 sun.nio.ch.EPollArrayWrapper.epollWait 14 3.14% 60.99% 40556 303478 sun.nio.ch.EPollArrayWrapper.epollWait 15 3.05% 64.04% 39428 303480 sun.nio.ch.EPollArrayWrapper.epollWait 16 2.68% 66.72% 34673 303477 sun.nio.ch.EPollArrayWrapper.epollWait 17 1.23% 67.95% 15867 303520 sun.nio.ch.EPollArrayWrapper.epollWait 18 0.98% 68.93% 12663 303541 sun.nio.ch.EPollArrayWrapper.epollWait 19 0.92% 69.85% 11920 303536 sun.nio.ch.EPollArrayWrapper.epollWait 20 0.85% 70.70% 11015 303546 sun.nio.ch.EPollArrayWrapper.epollWait 21 0.82% 71.53% 10625 303534 sun.nio.ch.EPollArrayWrapper.epollWait 22 0.69% 72.21% 8866 303512 sun.nio.ch.EPollArrayWrapper.epollWait
TransferTo to write data to socket, not actual CPU work (mostly) 23 0.36% 72.57% 4592 304991 sun.nio.ch.FileDispatcherImpl.write0 24 0.36% 72.92% 4589 305021 sun.nio.ch.FileDispatcherImpl.write0 25 0.35% 73.27% 4503 304992 sun.nio.ch.FileDispatcherImpl.write0 26 0.32% 73.60% 4198 305022 sun.nio.ch.FileDispatcherImpl.write0 27 0.25% 73.85% 3250 305246 sun.nio.ch.FileDispatcherImpl.write0 28 0.25% 74.10% 3249 305497 sun.nio.ch.FileDispatcherImpl.write0 Request channel - Actual CPU 29 0.22% 74.32% 2862 305000 sun.misc.Unsafe.unpark 30 0.17% 74.49% 2163 304838 sun.misc.Unsafe.unpark 31 0.14% 74.63% 1795 305240 sun.misc.Unsafe.unpark Purgatory - Actual CPU 32 0.12% 74.75% 1553 305137 scala.collection.immutable.HashMap.$plus 33 0.12% 74.87% 1546 305100 java.util.concurrent.ConcurrentHashMap.get 34 0.12% 74.98% 1531 305181 java.util.concurrent.ConcurrentHashMap.get 35 0.12% 75.10% 1526 305234 scala.collection.immutable.HashMap.$plus 36 0.12% 75.22% 1521 305401 scala.collection.immutable.HashMap.$plus 37 0.12% 75.34% 1519 305186 java.util.concurrent.ConcurrentHashMap.get 38 0.12% 75.46% 1517 305264 java.util.concurrent.ConcurrentHashMap.get 39 0.12% 75.57% 1514 305271 java.util.concurrent.ConcurrentHashMap.get 40 0.12% 75.69% 1511 305250 scala.collection.immutable.HashMap.$plus 41 0.12% 75.81% 1499 305155 java.util.concurrent.ConcurrentHashMap.get 42 0.12% 75.92% 1496 305113 scala.collection.immutable.HashMap.$plus 43 0.12% 76.04% 1496 305263 scala.collection.immutable.HashMap.$plus 44 0.11% 76.15% 1480 305235 scala.collection.immutable.HashMap.$plus 45 0.11% 76.26% 1444 305185 scala.collection.immutable.HashMap.$plus 46 0.11% 76.37% 1428 305102 java.util.concurrent.ConcurrentHashMap.get 47 0.11% 76.48% 1418 305320 java.util.concurrent.ConcurrentHashMap.get Compression - Actual CPU 48 0.09% 76.58% 1187 306546 org.xerial.snappy.SnappyNative.rawCompress 49 0.09% 76.67% 1174 305584 org.xerial.snappy.SnappyNative.rawCompress 50 0.09% 76.76% 1173 305545 org.xerial.snappy.SnappyNative.rawCompress 51 0.09% 76.85% 1165 305661 org.xerial.snappy.SnappyNative.rawCompress 52 0.09% 76.94% 1152 307069 org.xerial.snappy.SnappyNative.rawCompress 53 0.09% 77.02% 1121 305997 org.xerial.snappy.SnappyNative.rawCompress 54 0.09% 77.11% 1117 307035 org.xerial.snappy.SnappyNative.rawCompress 55 0.09% 77.19% 1106 306190 org.xerial.snappy.SnappyNative.rawCompress On Mon, Feb 2, 2015 at 9:39 AM, Jay Kreps <jay.kr...@gmail.com> wrote: > Ah, yeah, you're right. That is just wait time not CPU time. We should > check that profile it must be something else on the list. > > -Jay > > On Mon, Feb 2, 2015 at 9:33 AM, Jun Rao <j...@confluent.io> wrote: > >> Hi, Mathias, >> >> From the hprof output, it seems that the top CPU consumers are >> socketAccept() and epollWait(). As far as I am aware, there hasn't been >> any >> significant changes in the socket server code btw 0.8.1 and 0.8.2. Could >> you run the same hprof test on 0.8.1 so that we can see the difference? >> >> Jaikiran, >> >> The fix you provided in probably unnecessary. The channel that we use in >> SimpleConsumer (BlockingChannel) is configured to be blocking. So even >> though the read from the socket is in a loop, each read blocks if there is >> no bytes received from the broker. So, that shouldn't cause extra CPU >> consumption. >> >> Thanks, >> >> Jun >> >> On Mon, Jan 26, 2015 at 10:05 AM, Mathias Söderberg < >> mathias.soederb...@gmail.com> wrote: >> >> > Hi Neha, >> > >> > I sent an e-mail earlier today, but noticed now that it didn't actually >> go >> > through. >> > >> > Anyhow, I've attached two files, one with output from a 10 minute run >> and >> > one with output from a 30 minute run. Realized that maybe I should've >> done >> > one or two runs with 0.8.1.1 as well, but nevertheless. >> > >> > I upgraded our staging cluster to 0.8.2.0-rc2, and I'm seeing the same >> CPU >> > usage as with the beta version (basically pegging all cores). If I >> manage >> > to find the time I'll do another run with hprof on the rc2 version later >> > today. >> > >> > Best regards, >> > Mathias >> > >> > On Tue Dec 09 2014 at 10:08:21 PM Neha Narkhede <n...@confluent.io> >> wrote: >> > >> >> The following should be sufficient >> >> >> >> java >> >> -agentlib:hprof=cpu=samples,depth=100,interval=20,lineno= >> >> y,thread=y,file=kafka.hprof >> >> <classname> >> >> >> >> You would need to start the Kafka server with the settings above for >> >> sometime until you observe the problem. >> >> >> >> On Tue, Dec 9, 2014 at 3:47 AM, Mathias Söderberg < >> >> mathias.soederb...@gmail.com> wrote: >> >> >> >> > Hi Neha, >> >> > >> >> > Yeah sure. I'm not familiar with hprof, so any particular options I >> >> should >> >> > include or just run with defaults? >> >> > >> >> > Best regards, >> >> > Mathias >> >> > >> >> > On Mon Dec 08 2014 at 7:41:32 PM Neha Narkhede <n...@confluent.io> >> >> wrote: >> >> > >> >> > > Thanks for reporting the issue. Would you mind running hprof and >> >> sending >> >> > > the output? >> >> > > >> >> > > On Mon, Dec 8, 2014 at 1:25 AM, Mathias Söderberg < >> >> > > mathias.soederb...@gmail.com> wrote: >> >> > > >> >> > > > Good day, >> >> > > > >> >> > > > I upgraded a Kafka cluster from v0.8.1.1 to v0.8.2-beta and >> noticed >> >> > that >> >> > > > the CPU usage on the broker machines went up by roughly 40%, from >> >> ~60% >> >> > to >> >> > > > ~100% and am wondering if anyone else has experienced something >> >> > similar? >> >> > > > The load average also went up by 2x-3x. >> >> > > > >> >> > > > We're running on EC2 and the cluster currently consists of four >> >> > > m1.xlarge, >> >> > > > with roughly 1100 topics / 4000 partitions. Using Java 7 >> (1.7.0_65 >> >> to >> >> > be >> >> > > > exact) and Scala 2.9.2. Configurations can be found over here: >> >> > > > https://gist.github.com/mthssdrbrg/7df34a795e07eef10262. >> >> > > > >> >> > > > I'm assuming that this is not expected behaviour for 0.8.2-beta? >> >> > > > >> >> > > > Best regards, >> >> > > > Mathias >> >> > > > >> >> > > >> >> > > >> >> > > >> >> > > -- >> >> > > Thanks, >> >> > > Neha >> >> > > >> >> > >> >> >> >> >> >> >> >> -- >> >> Thanks, >> >> Neha >> >> >> > >> > >
