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From Mathias Söderberg <mathias.soederb...@gmail.com>
Subject Re: Increased CPU usage with 0.8.2-beta
Date Mon, 02 Feb 2015 21:15:16 GMT
Hi all,

I ran the same hprof test on 0.8.1.1, and also did a re-run on 0.8.2.0-rc2,
attached logs from both runs. Both runs lasted for 30-40 minutes. The
configurations used can be found over here:
https://gist.github.com/mthssdrbrg/5fcb9fbdb851d8cc66a2. The configuration
used for the first run (on 0.8.2-beta) can be found here:
https://gist.github.com/mthssdrbrg/7df34a795e07eef10262.

The cluster is running on EC2, currently on 4 m1.xlarge, with a ZooKeeper
cluster consisting of 3 nodes. There's 1248 topics, and a total of 4143
partitions, using replication factor 3.

Let me know if there's any other information I can provide.

Best regards,
Mathias

On Mon Feb 02 2015 at 6:50:54 PM Jay Kreps <jay.kreps@gmail.com> wrote:

> 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.kreps@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 <jun@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.soederberg@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 <neha@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.soederberg@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 <neha@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.soederberg@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
> >> >>
> >> >
> >>
> >
> >
>

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