RFR(S): 8242848: Improve performance of InflaterOutputStream.write()

Volker Simonis volker.simonis at gmail.com
Thu Apr 23 10:18:45 UTC 2020 

On Thu, Apr 23, 2020 at 10:56 AM Laurent Bourgès
<bourges.laurent at gmail.com> wrote:
>
> Hi Volker,
>
> Could you give some benchmark results in the jbs bug to have an idea of the performance gain ?

The results of a benchmark run are at the end of the microbenchmark
which is attached to https://bugs.openjdk.java.net/browse/JDK-8242848

I've attached them here for your convenience. The first run is before,
the second run after applying this patch.

E.g. for a user supplied buffer of size 16384, the time for inflation
decreases from "2.603 ± 0.404  ms/op" to "2.187 ± 0.126  ms/op" which
is an improvement of 16%. Obviously, increasing the default internal
buffer size from 512 to 16384 (which I want to do in
https://bugs.openjdk.java.net/browse/JDK-8242864) will get you even
bigger speedups if you use the default buffer size :)

/output/jdk-opt/images/jdk/bin/java
----------------------------------------------------------------------
Benchmark                        (scale)  (size)  Mode  Cnt  Score
Error  Units
InflaterOutputStreamWrite.write        1     512  avgt    3  5.378 ±
0.301  ms/op
InflaterOutputStreamWrite.write        1    1024  avgt    3  3.917 ±
0.165  ms/op
InflaterOutputStreamWrite.write        1    2048  avgt    3  3.158 ±
0.097  ms/op
InflaterOutputStreamWrite.write        1    4096  avgt    3  2.707 ±
0.138  ms/op
InflaterOutputStreamWrite.write        1    8192  avgt    3  2.600 ±
0.399  ms/op
InflaterOutputStreamWrite.write        1   16384  avgt    3  2.603 ±
0.404  ms/op
InflaterOutputStreamWrite.write        1   32768  avgt    3  2.622 ±
0.211  ms/op
InflaterOutputStreamWrite.write        1   65536  avgt    3  2.605 ±
0.170  ms/op
InflaterOutputStreamWrite.write        2     512  avgt    3  4.015 ±
0.150  ms/op
InflaterOutputStreamWrite.write        2    1024  avgt    3  3.225 ±
0.178  ms/op
InflaterOutputStreamWrite.write        2    2048  avgt    3  2.745 ±
0.261  ms/op
InflaterOutputStreamWrite.write        2    4096  avgt    3  2.614 ±
0.542  ms/op
InflaterOutputStreamWrite.write        2    8192  avgt    3  2.593 ±
0.206  ms/op
InflaterOutputStreamWrite.write        2   16384  avgt    3  2.606 ±
0.055  ms/op
InflaterOutputStreamWrite.write        2   32768  avgt    3  2.611 ±
0.116  ms/op
InflaterOutputStreamWrite.write        2   65536  avgt    3  2.617 ±
0.170  ms/op
InflaterOutputStreamWrite.write        4     512  avgt    3  3.376 ±
0.599  ms/op
InflaterOutputStreamWrite.write        4    1024  avgt    3  2.840 ±
0.155  ms/op
InflaterOutputStreamWrite.write        4    2048  avgt    3  2.633 ±
0.550  ms/op
InflaterOutputStreamWrite.write        4    4096  avgt    3  2.598 ±
0.166  ms/op
InflaterOutputStreamWrite.write        4    8192  avgt    3  2.602 ±
0.054  ms/op
InflaterOutputStreamWrite.write        4   16384  avgt    3  2.601 ±
0.039  ms/op
InflaterOutputStreamWrite.write        4   32768  avgt    3  2.639 ±
0.020  ms/op
InflaterOutputStreamWrite.write        4   65536  avgt    3  2.619 ±
0.260  ms/op
InflaterOutputStreamWrite.write        8     512  avgt    3  2.882 ±
0.149  ms/op
InflaterOutputStreamWrite.write        8    1024  avgt    3  2.695 ±
0.586  ms/op
InflaterOutputStreamWrite.write        8    2048  avgt    3  2.644 ±
0.472  ms/op
InflaterOutputStreamWrite.write        8    4096  avgt    3  2.616 ±
0.052  ms/op
InflaterOutputStreamWrite.write        8    8192  avgt    3  2.616 ±
0.063  ms/op
InflaterOutputStreamWrite.write        8   16384  avgt    3  2.611 ±
0.090  ms/op
InflaterOutputStreamWrite.write        8   32768  avgt    3  2.633 ±
0.216  ms/op
InflaterOutputStreamWrite.write        8   65536  avgt    3  2.634 ±
0.180  ms/op

/priv/simonisv/output/jdk-opt-JDK-8242848/images/jdk/bin/java
----------------------------------------------------------------------
Benchmark                        (scale)  (size)  Mode  Cnt  Score
Error  Units
InflaterOutputStreamWrite.write        1     512  avgt    3  5.388 ±
0.349  ms/op
InflaterOutputStreamWrite.write        1    1024  avgt    3  3.799 ±
0.093  ms/op
InflaterOutputStreamWrite.write        1    2048  avgt    3  2.994 ±
0.023  ms/op
InflaterOutputStreamWrite.write        1    4096  avgt    3  2.583 ±
0.159  ms/op
InflaterOutputStreamWrite.write        1    8192  avgt    3  2.325 ±
0.345  ms/op
InflaterOutputStreamWrite.write        1   16384  avgt    3  2.187 ±
0.126  ms/op
InflaterOutputStreamWrite.write        1   32768  avgt    3  2.073 ±
0.083  ms/op
InflaterOutputStreamWrite.write        1   65536  avgt    3  2.007 ±
0.153  ms/op
InflaterOutputStreamWrite.write        2     512  avgt    3  3.996 ±
0.037  ms/op
InflaterOutputStreamWrite.write        2    1024  avgt    3  3.089 ±
0.023  ms/op
InflaterOutputStreamWrite.write        2    2048  avgt    3  2.628 ±
0.073  ms/op
InflaterOutputStreamWrite.write        2    4096  avgt    3  2.356 ±
0.344  ms/op
InflaterOutputStreamWrite.write        2    8192  avgt    3  2.202 ±
0.055  ms/op
InflaterOutputStreamWrite.write        2   16384  avgt    3  2.081 ±
0.033  ms/op
InflaterOutputStreamWrite.write        2   32768  avgt    3  2.015 ±
0.169  ms/op
InflaterOutputStreamWrite.write        2   65536  avgt    3  1.985 ±
0.196  ms/op
InflaterOutputStreamWrite.write        4     512  avgt    3  3.325 ±
0.920  ms/op
InflaterOutputStreamWrite.write        4    1024  avgt    3  2.740 ±
0.156  ms/op
InflaterOutputStreamWrite.write        4    2048  avgt    3  2.415 ±
0.370  ms/op
InflaterOutputStreamWrite.write        4    4096  avgt    3  2.250 ±
0.012  ms/op
InflaterOutputStreamWrite.write        4    8192  avgt    3  2.115 ±
0.085  ms/op
InflaterOutputStreamWrite.write        4   16384  avgt    3  2.042 ±
0.099  ms/op
InflaterOutputStreamWrite.write        4   32768  avgt    3  1.988 ±
0.185  ms/op
InflaterOutputStreamWrite.write        4   65536  avgt    3  1.975 ±
0.171  ms/op
InflaterOutputStreamWrite.write        8     512  avgt    3  2.870 ±
0.035  ms/op
InflaterOutputStreamWrite.write        8    1024  avgt    3  2.495 ±
0.334  ms/op
InflaterOutputStreamWrite.write        8    2048  avgt    3  2.280 ±
0.056  ms/op
InflaterOutputStreamWrite.write        8    4096  avgt    3  2.155 ±
0.073  ms/op
InflaterOutputStreamWrite.write        8    8192  avgt    3  2.046 ±
0.079  ms/op
InflaterOutputStreamWrite.write        8   16384  avgt    3  1.995 ±
0.098  ms/op
InflaterOutputStreamWrite.write        8   32768  avgt    3  1.979 ±
0.119  ms/op
InflaterOutputStreamWrite.write        8   65536  avgt    3  1.986 ±
0.155  ms/op

>
> Thanks,
> Laurent
>
> Le jeu. 23 avr. 2020 à 10:20, Langer, Christoph <christoph.langer at sap.com> a écrit :
>>
>> Hi Volker,
>>
>> since it's not yet pushed, I also went over the change and I like it. +1
>>
>> One little style nit caught my eye, which you could correct before pushing: The style of the if/else blocks in test/jdk/java/util/zip/DeflateIn_InflateOut.java in lines 48/49 and 59/60 does not match the other if/else blocks in the file. You should probably have the else on the line of the closing bracket before...
>>
>> Thanks
>> Christoph
>>
>>
>> > -----Original Message-----
>> > From: core-libs-dev <core-libs-dev-bounces at openjdk.java.net> On Behalf
>> > Of Volker Simonis
>> > Sent: Mittwoch, 22. April 2020 22:09
>> > To: Lance Andersen <lance.andersen at oracle.com>
>> > Cc: Java Core Libs <core-libs-dev at openjdk.java.net>; Vyom Tewari
>> > <vyom.tewari at oracle.com>
>> > Subject: Re: RFR(S): 8242848: Improve performance of
>> > InflaterOutputStream.write()
>> >
>> > On Tue, Apr 21, 2020 at 5:23 PM Lance Andersen
>> > <lance.andersen at oracle.com> wrote:
>> > >
>> > > Hi Volker,
>> > >
>> > > I think overall this looks OK.  I went through the older SCCS histories to see
>> > if I could figure out why they were using 512 for the input length but could
>> > not find anything that might shed some light for me.
>> > >
>> >
>> > Hi Lance,
>> >
>> > thanks a lot for digging in the old sources to review my change. It's
>> > great that we stil have people who can use SCCS :)
>> >
>> > > I am not sure you can guarantee that src.zip exists but others might be able
>> > to weigh in here.  What we have been trying to do going forward is to have
>> > the tests create  the zip files that it needs.  In some cases, we have created a
>> > byte array within the test which represents the zip and just write it out
>> > before the test begins.
>> > >
>> >
>> > Yes, the dependency on an external file was not nice, so I rewrote the
>> > benchmark to programmatically create a file which can be compressed by
>> > a factor of ~6:
>> >
>> > http://cr.openjdk.java.net/~simonis/webrevs/2020/8242848.02/
>> >
>> > Notice that this new version only changes the microbenchmark, all the
>> > other files are untouched.
>> >
>> > As everybody seemed to be happy with the change itself and the
>> > regression test, I'm now waiting for your and Clae's final review of
>> > the microbenchmark before pushing. Please let me know hat you think?
>> >
>> > Best regards,
>> > Volker
>> >
>> > > I am hoping others with more history might also chime in case they are
>> > aware of the history here.
>> > >
>> > > Thank you for helping improve the performance.
>> > >
>> > > Best
>> > > Lance
>> > >
>> > > On Apr 17, 2020, at 6:49 AM, Volker Simonis <volker.simonis at gmail.com>
>> > wrote:
>> > >
>> > > Thanks everybody for looking at this change!
>> > >
>> > > Please find an updated webrev (with a new test and micro-benchmark)
>> > > and my answers to your comments below:
>> > >
>> > > http://cr.openjdk.java.net/~simonis/webrevs/2020/8242848.01/
>> > >
>> > > On Thu, Apr 16, 2020 at 6:40 AM Vyom Tiwari <vyommani at gmail.com>
>> > wrote:
>> > >
>> > > Thanks for doing this, i think the below code change is not required .
>> > >
>> > > Please do let me know if i am not reading it correctly.
>> > >
>> > > if (inf.finished() || (len == 0)/* no more input */) {
>> > >
>> > > If you check the native code "inf.finished() will be true only of the
>> > corresponding native call inflate(strm, Z_PARTIAL_FLUSH) returns
>> > "Z_STREAM_END".
>> > >
>> > > After your code change  write may return even if finished() is not true.
>> > >
>> > >
>> > > Yes, that's true, but that's what we must do if there's no more input
>> > > available. Before my change this break on "len < 1" was in the "if
>> > > (inf.needsInput())" branch.
>> > >
>> > > On Thu, Apr 16, 2020 at 8:22 AM Thomas Stüfe
>> > <thomas.stuefe at gmail.com> wrote:
>> > >
>> > > 252                 // Check the decompressor
>> > > 253                 if (inf.finished() || (len == 0)/* no more input */) {
>> > > 254                     break;
>> > > 255                 }
>> > >
>> > > Not sure but I think this is wrong because now you bypass the followup
>> > handling of inf.needsDirectory.
>> > >
>> > > Inflater.inflate() returns 0 if either needsInput or needsDirectory. We have
>> > to ignore needsInput since we have no input anymore, but needsDirectory
>> > has to be handled, no?
>> > >
>> > >
>> > > You're absolutely right Thomas. Thanks for catching this! I've moved
>> > > the check for "needsDictionary" in front of the "finished() || len ==
>> > > 0" check.
>> > >
>> > > Unfortunately there is not very good test coverage for zip with preset
>> > > dictionaries (jtreg and submit repo passed without problems). So I
>> > > added a new test for this use case to "
>> > > test/jdk/java/util/zip/DeflateIn_InflateOut.java".
>> > >
>> > > On Thu, Apr 16, 2020 at 8:48 AM Thomas Stüfe
>> > <thomas.stuefe at gmail.com> wrote:
>> > >
>> > >
>> > > As for increasing the buffer size, it makes sense but IMHO needs a CSR and
>> > a release note.
>> > >
>> > >
>> > > I don't think so. This is an internal, implementation specific setting
>> > > which has never been exposed or documented before so I don't see why
>> > > we should document it now. But let's discuss this separately in the
>> > > corresponding JBS issue (see below).
>> > >
>> > > On Thu, Apr 16, 2020 at 1:18 PM Claes Redestad
>> > > <claes.redestad at oracle.com> wrote:
>> > >
>> > >
>> > > Hi Volker,
>> > >
>> > > On 2020-04-15 19:48, Volker Simonis wrote:
>> > >
>> > > While doing this change, I've also realized that all the streams in
>> > > java.util.zip (i.e. DeflaterInputStream, GZIPInputStream,
>> > > GZIPOutputStream, InflaterInputStream, DeflaterOutputStream) use an
>> > > internal byte buffer of 512 bytes by default. Looking at the benchmark
>> > > attached to JDK-8242864, I think that increasing this default to a
>> > > bigger size (e.g. 4096 bytes) will considerably speed up (up to 50%)
>> > > read and write operations on these streams when they are created with
>> > > the default buffer size. I think the value "512" is a legacy of old
>> > > times when memory was more precious:)  so  I've opened "JDK-8242864:
>> > > Increase the default, internal buffer size of the Streams in
>> > > java.util.zip" to track that as as separate issue. Do you think it
>> > > makes sense to increase that default value?
>> > >
>> > >
>> > > Seems reasonable. 8192 seems to be the buffer size we've been
>> > converging
>> > > on elsewhere (see InputStream, BufferedInputStream, Files, ..). I also
>> > >
>> > >
>> > > That seems reasonable. Alan commented on the JBS issue so we can
>> > > continue the discussion there.
>> > >
>> > > found an instance of 8096, which is either a typo or a clever
>> > > optimization to keep the array + array object header fit snugly within
>> > > 8Kb. You chose. :-)
>> > >
>> > >
>> > > I like how you try to be positive :)
>> > >
>> > >
>> > > Thank you and best regards,
>> > > Volker
>> > >
>> > > PS: do you think it makes sense to contribute the benchmark attached
>> > > to JDK-8242864 to the code-tools/mh-jdk-microbenchmarks [1] project?
>> > >
>> > > [1]http://openjdk.java.net/projects/code-tools/jmh-jdk-
>> > microbenchmarks/
>> > >
>> > >
>> > > I'd definitely welcome the micro as part of the patch under
>> > > test/micro/org/openjdk/bench/java/util/zip - additionally contributing
>> > >
>> > >
>> > > I knew that "jmh-jdk-microbenchmarks" has been copied to the jdk repo
>> > > but somehow I did found "jmh-jdk-microbenchmarks" before looking in
>> > > the obvious place :)
>> > >
>> > > So I've added the benchmark to the patch now. There's one thing I'm
>> > > not sure however. The benchmark requires a "big" (several 100k) with
>> > > good compression ratio (e.g. a large text file). I've decided to use a
>> > > big Java source file from "src.zip" but I'm not sure if "src.zip" is
>> > > always available in the jdk images which are used to run the
>> > > microbenchmarks. Do you think the test it is fine this way or do you
>> > > have a better idea? I saw that "ZipFind" uses "microbenchmarks.jar"
>> > > (i.e. the container of the test itself) but that file is already
>> > > compressed so the compression rate won't be that good.
>> > >
>> > > Another thing I couldn't figure out is a good way to skip the
>> > > benchmark when I realize that I can't load the expected file in the
>> > > "@Setup" method. Do you now anything better than just throwing an
>> > > exception?
>> > >
>> > > Thank you and best regards,
>> > > Volker
>> > >
>> > > to jmh-jdk-microbenchmarks could enable you to test the micro on 8 or
>> > > 11.
>> > >
>> > > /Claes
>> > >
>> > >
>> > >
>> > > Lance Andersen| Principal Member of Technical Staff | +1.781.442.2037
>> > > Oracle Java Engineering
>> > > 1 Network Drive
>> > > Burlington, MA 01803
>> > > Lance.Andersen at oracle.com
>> > >
>> > >
>> > >

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