Java Performance Degradation in JDK7 and JDK8
Jacob Wieland
wieland at testingtech.com
Wed Apr 29 14:06:39 UTC 2015
I have to admit, the reproducer is only a small part of the actual
generated code. In my preliminary tests, it already sufficed to show a
difference (also, the smaller code still worked with 32 bit while the whole
code runs out of memory in all 32 bit versions which makes comparison much
harder ;-) and which is why I need the 64 bit versions). If I test with the
complete code which is much bigger, the results are as follows:
jdk1.6u45(64bit) 2GB MaxMem - 1:30 minutes
jdk1.7u75(64bit) 2GB MaxMem - > 6 min
jdk1.8u31(64bit) 1GB MaxMem - > 15 min
jdk1.8u31(64bit) 2GB MaxMem - > 10 min
jdk1.8u31(64bit) 4GB MaxMem - 2:20 min (-source/-target 6 does not seem to
have any effect)
So, if you throw insane (in comparison with 1.6) amounts of memory at
1.7/1.8, it is only about a third as slow, but this still is unacceptable.
I actually think it has to do with parallellization and garbage collection.
2015-04-29 15:12 GMT+02:00 Maurizio Cimadamore <
maurizio.cimadamore at oracle.com>:
> On 29/04/15 12:44, Jacob Wieland wrote:
>
> Hello Maurizio,
>
> are you sure that you used the 64bit versions of javac? I could only
> observe the behavior with these.
>
> Yep I'm on a Ubuntu x64 machine. It's actually pretty standard hardware
> too - i.e. intel i5 (two cores, but OS sees 4 because of hyper-threading).
>
> Also, I just tried with jdk8u31-64b and it takes AGES (still running
> after 17 minutes where the jdk6 was done after 2), top shows 4GB VIRT
> memory use and 350 % load (on a 4core processor).
>
> Maybe the reproducer you sent was incorrect?
>
> Maurizio
>
>
> So, I don't think it was that problem.
>
> 2015-04-29 12:00 GMT+02:00 Maurizio Cimadamore <
> maurizio.cimadamore at oracle.com>:
>
>> These are the numbers I'm getting:
>>
>> JDK 9 (b42)
>>
>> Note: generated_ttcn/TTCN3_CommonDefs.java uses or overrides a deprecated
>> API.
>> Note: Recompile with -Xlint:deprecation for details.
>>
>> real 0m46.306s
>> user 2m17.489s
>> sys 0m2.166s
>>
>> JDK 8 (GA)
>>
>> Note: generated_ttcn/TTCN3_CommonDefs.java uses or overrides a deprecated
>> API.
>> Note: Recompile with -Xlint:deprecation for details.
>>
>> real 6m58.748s
>> user 8m43.546s
>> sys 0m2.132s
>>
>> JDK 7 (1.7.0_79)
>>
>> Note: generated_ttcn/TTCN3_CommonDefs.java uses or overrides a deprecated
>> API.
>> Note: Recompile with -Xlint:deprecation for details.
>>
>> real 0m28.341s
>> user 1m17.194s
>> sys 0m1.886s
>>
>>
>> As you can see there is a significant regression from JDK 7 to JDK 8
>> which was caused by
>>
>> https://bugs.openjdk.java.net/browse/JDK-8043253
>>
>> (some stack trace analysis revealed the familiar pattern). This has also
>> been fixed in JDK 8u20 (as stated in the bug evaluation).
>>
>> So, while JDK 8u20/9 is slower than JDK 7 (at least on my machine), the
>> numbers are more or less in the same ballpark and the huge regression that
>> was visible in earlier JDK 8 releases has now been fixed.
>>
>> If you are still experiencing the problem - can you please also submit
>> the specific compiler versions you are using in your benchmark?
>>
>> Maurizio
>>
>>
>>
>> On 29/04/15 10:29, Maurizio Cimadamore wrote:
>>
>> Hi Jacob,
>> Stay assured - as we'll definitively look into this issue (I see it's
>> already assigned to one of my colleagues).
>>
>> What I can say (w/o looking too much at the attached artifacts) is that
>> in general, javac has no issue with compiling a lot of sources at once; at
>> one point the build system was structured in such a way that all the JDK
>> classes were compiled at once - and that (which is way more than your 187
>> sources - i.e. at least 10x that) took less than 20 seconds. SO there must
>> some specific pattern triggering that issue.
>>
>> Given that you say you have 187 input sources and 48K output classes, I'd
>> say you are using inner classes a lot. I wonder if you are hitting this:
>>
>> https://bugs.openjdk.java.net/browse/JDK-8000316
>>
>> Maurizio
>>
>> On 24/04/15 09:49, Jacob Wieland wrote:
>>
>> Hello Folks,
>>
>>
>> I still have the open problem
>> https://bugs.openjdk.java.net/browse/JDK-8039262 that the javac
>> performance has degraded significantly from 1.6 to 1.7 (and even worse to
>> 1.8) in the 64bit versions. Since in our context, we are dealing with a lot
>> of generated source1.4 Java input (either split into very large files with
>> inner classes or big packages with lots of smaller classes), compiler
>> performance is critical for our tool and this degradation forces us to
>> continue recommending to our customers to use Java 1.6 for large projects
>> (as is the norm) as 1.7 and 1.8 are pretty much unusable in this respect.
>>
>> Is anyone still working on this issue or is such significant
>> performance degradation not a serious issue?
>>
>> My observations so far are:
>> - it gets worse the more class files are being compiled/the more files
>> reside in the source path
>> - cpu usage goes through the roof over all available kernels
>> - memory usage is much higher
>> - garbage collection seems to be much more active
>>
>> Using -proc:none alleviates the problem slightly for the 1.7 version,
>> but not for 1.8 (last we tested with jdk1.8.0_31) where the performance
>> difference is a factor 5 or more!
>>
>> I can understand that a more advanced compiler has capabilities that a
>> previous version does not have and thus sometimes has
>> to do more work. But, it should still be possible (especially if given
>> the -source 1.4 or -source 1.5 option as we do) to optimize it in such a
>> way that unnecessary checks for generics, overriding methods, closures,
>> annotations and other newer features can be turned off (if they are to
>> blame, which I actually doubt from my observations).
>>
>> I would really appreciate your help in this regard and I think everyone
>> would benefit from any bugfix you can offer for this.
>>
>> BR, Jacob Wieland
>>
>> --
>> --
>> ------------------------------
>> -------------------------------------------
>> Dr. Jacob Wieland
>> Senior Software Engineer
>>
>> Testing Technologies IST GmbH
>> Michaelkirchstraße 17/18
>> 10179 Berlin, Germany
>>
>> Phone +49 30 726 19 19 34 Email wieland at testingtech.com
>> <stanca at testingtech.com>
>> Fax +49 30 726 19 19 20 Internet www.testingtech.com
>>
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>
>
> --
> --
> ------------------------------
> -------------------------------------------
> Dr. Jacob Wieland
> Senior Software Engineer
>
> Testing Technologies IST GmbH
> Michaelkirchstraße 17/18
> 10179 Berlin, Germany
>
> Phone +49 30 726 19 19 34 Email wieland at testingtech.com
> <stanca at testingtech.com>
> Fax +49 30 726 19 19 20 Internet www.testingtech.com
>
> ---------------------------------------------------------------------------------------------------------------
>
>
> -----------------------------------------------------------------------------------------------------------------
>
> UPCOMING EVENTS
>
> SUBMIT YOUR TOPIC for the UCAAT 2015
> Deadline: May 30, 2015ucaat.etsi.org/2015/CallForPresentations.html
>
> Apr 21-23, 2015 | SAE Conference & Exhibition
> Detroit, Michigan, USAwww.sae.org/congress/
>
> Apr 28-30, 2015 | iqnite
> Dusseldorf, Germanywww.iqnite-conferences.com/de/index.aspx
>
> -----------------------------------------------------------------------------------------------------------------
> Geschäftsführung: Theofanis Vassiliou-Gioles, Stephan Pietsch, Pete
> Nicholson Handelsregister HRB 77805 B, Amtsgericht Charlottenburg Ust ID
> Nr.: DE 813 143 070 This email may contain confidential and privileged
> material for the sole use of the intended recipient. Any review, use,
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--
--
------------------------------
-------------------------------------------
Dr. Jacob Wieland
Senior Software Engineer
Testing Technologies IST GmbH
Michaelkirchstraße 17/18
10179 Berlin, Germany
Phone +49 30 726 19 19 34 Email wieland at testingtech.com
<stanca at testingtech.com>
Fax +49 30 726 19 19 20 Internet www.testingtech.com
---------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------------------------
UPCOMING EVENTS
SUBMIT YOUR TOPIC for the UCAAT 2015
Deadline: May 30, 2015ucaat.etsi.org/2015/CallForPresentations.html
Apr 21-23, 2015 | SAE Conference & Exhibition
Detroit, Michigan, USAwww.sae.org/congress/
Apr 28-30, 2015 | iqnite
Dusseldorf, Germanywww.iqnite-conferences.com/de/index.aspx
-----------------------------------------------------------------------------------------------------------------
Geschäftsführung: Theofanis Vassiliou-Gioles, Stephan Pietsch, Pete
Nicholson Handelsregister HRB 77805 B, Amtsgericht Charlottenburg Ust ID
Nr.: DE 813 143 070 This email may contain confidential and privileged
material for the sole use of the intended recipient. Any review, use,
distribution or disclosure by others is strictly prohibited. If you are not
the intended recipient (or authorized to receive for the recipient), please
contact the sender by reply email and delete all copies of this message.
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