Request for Review - 8152208: Summary for phase times are incorrect with and without UseDynamicNumberOfGCThreads

Tao Mao yiyeguhu at gmail.com
Mon Mar 21 22:16:38 UTC 2016


This change has a bug: double counting get(0); should start with s = 0

Thanks.
Tao Mao

On Mon, Mar 21, 2016 at 2:55 PM, Jon Masamitsu <jon.masamitsu at oracle.com>
wrote:

> Bengt,
>
> Thanks for the review.
>
> On 03/21/2016 02:13 AM, Bengt Rutisson wrote:
>
>
> Hi Jon,
>
> On 2016-03-21 03:43, Jon Masamitsu wrote:
>
> The averages reported for phase times (for example "Ext Root Scanning")
> were
> incorrect.  Not all the per thread values were included in the sum and the
> average value was incorrect (this with build 9-ea+1100)
>
> [0.366s][debug][gc,phases            ] GC(2)     Ext Root Scanning (ms):
> Min:  0.3, Avg:  0.2, Max:  0.4, Diff:  0.0, Sum:  0.3
> [0.366s][trace][gc,phases,task       ]
> GC(2)                                0.4  0.3
>
> With the fix all values are included in the sum and the average is
> correct.
>
> [2.830s][debug][gc,phases            ] GC(0)     Ext Root Scanning (ms):
> Min:  5.7, Avg:  7.3, Max:  8.9, Diff:  3.1, Sum: 14.6
> [2.830s][trace][gc,phases,task       ]
> GC(0)                                8.9  5.7
>
> https://bugs.openjdk.java.net/browse/JDK-8152208
> http://cr.openjdk.java.net/~jmasa/8152208/webrev.00/
>
>
> Nice catch! Your change looks good.
>
> The method WorkerDataArray<T>::sum(uint active_threads) just above the
> average() method has the same issue. Can you fix that too?
>
>
> Yes, indeed.
>
> I messed up the delta a bit so all the changes are in the
> workerDataArray.inline.hpp
> webrev.  The test has not changed.
>
> http://cr.openjdk.java.net/~jmasa/8152208/webrev.01/
>
> Jon
>
>
> Thanks,
> Bengt
>
>
> Thanks.
>
> Jon
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/attachments/20160321/b65bf67f/attachment-0001.html>


More information about the hotspot-gc-dev mailing list