Fwd: Fwd: Re: Request for review: 8004132 SerialGC ValidateMarkSweep code broken

John Cuthbertson john.cuthbertson at oracle.com
Thu Dec 20 15:02:23 PST 2012


Forwarding to the GC dev list.

JohnC

-------- Original Message --------
Subject: 	Fwd: Re: Request for review: 8004132 SerialGC 
ValidateMarkSweep code broken
Date: 	Thu, 20 Dec 2012 14:19:24 -0800
From: 	Tao Mao <tao.mao at oracle.com>
Organization: 	Oracle Corporation
To: 	hotspot-dev at openjdk.java.net <hotspot-dev at openjdk.java.net>



Hi hotspot-dev,
Is there anyone interested in reviewing the change?

Thanks.
Tao

-------- Original Message --------
Subject: 	Re: Request for review: 8004132 SerialGC ValidateMarkSweep
code broken
Date: 	Mon, 17 Dec 2012 13:02:15 -0800
From: 	Tao Mao <tao.mao at oracle.com>
Organization: 	Oracle Corporation
To: 	John Cuthbertson <john.cuthbertson at oracle.com>
CC: 	hotspot-gc-dev openjdk.java.net <hotspot-gc-dev at openjdk.java.net>



Thank you, John. A new webrev is uploaded as you advised.

http://cr.openjdk.java.net/~tamao/8004132/webrev.01/

I would like to have one more review if possible.

Thanks.
Tao

On 12/13/2012 4:05 PM, John Cuthbertson wrote:
>  Hi Tao,
>
>  This looks good to me. One comment - the functionality of
>  RecordMarkSweepCompaction depends upon ValidateMarkSweep you might
>  want to remove this flag as well.
>
>  JohnC
>
>  On 12/04/12 15:47, Tao Mao wrote:
>>  8004132 : SerialGC: ValidateMarkSweep broken when running GCOld
>>  http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8004132
>>
>>  http://cr.openjdk.java.net/~tamao/8004132/webrev.00/
>>
>>  Passed JPRT; I checked ValidateMarkSweep can't be triggered now with
>>  the fix.
>>
>>  Background:
>>
>>  While verifying the functionality of the ValidateMarkSweep code with
>>  the Serial collector (prior to adding code to enable this feature in
>>  G1) Tao and myself saw various crashes and failures when running GC Old.
>>
>>  Script to run GCOld:
>>  #JHOME=/export/jdk8/solaris-x64
>>  #JHOME=/java/re/jdk/6/promoted/latest/binaries/solaris-i586/fastdebug
>>  JHOME=/export/bugs/8001047/jdk7/solaris-x64
>>
>>  $JHOME/bin/java -server -Xms1g -Xmx1g \
>>          -XX:+UseSerialGC \
>>          -XX:+ValidateMarkSweep \
>>          -XX:+PrintGCDetails -XX:+PrintGCTimeStamps
>>  -XX:+ShowMessageBoxOnError \
>>                  GCOld 9000 20 5 30 500000
>>
>>  Note the ValidateMarkSweep functionality is only available in
>>  non-product builds.
>>
>>  This seems to have been broken for a long while - we even saw the
>>  crash with jdk6. Thus we suggest to remove the ValidateMarkSweep code.
>>
>



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