Javac performance degradation of JDK 7 vs. 6

Thu Jul 17 06:55:58 UTC 2014

Thank you for investigating. I'm glad that it can be reproduced and does
not only happen to me. I'm sure that a fix for this will greatly benefit
everyone.

BR, Jacob

2014-07-16 15:54 GMT+02:00 Jan Lahoda <jan.lahoda at oracle.com>:

> Hello Jacob,
>
> I am looking at the issue a little bit. This will probably need a deeper
> investigation, but there indeed seems to be a considerable difference in
> compilation times of the testcase between JDK 6 64bit and JDK 7 64 bit when
> the annotation processing is enabled, even if given enough heap size. I am
> not yet clear on what is the cause.
>
> Thanks,
>     Jan
>
>
> On 14.7.2014 22:10, Jacob Wieland wrote:
>
>> Hello folks,
>>
>> Some time ago, I have raised the issue
>> https://bugs.openjdk.java.net/browse/JDK-8039262 and now have been
>> referred to you
>> gentle people in the hope that someone might have some ideas and the
>> time and energy to resolve it.
>>
>> It is about a serious javac performance degradation in the 64 bit
>> version of Java 7 (and higher) in comparison to the 64 bit version
>> of Java 6. If annotation processing is not specifically turned off
>> (which helps somewhat, even though performance is still 10% or so worse
>> than for Java 6), the same java code very often takes several minutes
>> instead of 40 to 50 seconds to compile. Also, it uses much more CPU (all
>> 4 cores of my computer seem to be fully busy) and memory in the process.
>> My guess is that there is some paralellization optimization going on
>> that in our case is a pessimization, probably involving garbage
>> collection (as that is where the compiler seems to be spending its time
>> mainly, regardless how much memory I throw at it (more memory actually
>> seems to make it worse) if looking at -verbose:gc is to be believed.
>>
>> Also, there seems to be a serious problem regarding source-file-lookup
>> in large packages (containing thousands of source files).
>>
>> If there are any further questions that are not covered by the bug in
>> the mentioned link, I'm happy to answer them.
>>
>> Thanks for your help,
>>
>> Jacob
>>
>> --
>> --
>> ------------------------------
>> -------------------------------------------
>> 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
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>>
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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

Sep 7-11, 2014 | World Congress on Intelligent Transport Systems

Detroit, Michigan, USA

www.itsworldcongress.org/

Sep 16-18, 2014 | User Conference on Advanced Automated Testing

Munich, Germany

www.ucaat.etsi.org/2014/index.html

Sep 23-25, 2014 | Accredited TTCN-3 Training

Berlin, Germany

www.testingtech.com/services/ttcn3_training.php

-----------------------------------------------------------------------------------------------------------------

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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