RFR: JDK-8152952: Allow G1 phase logging to use individual number of threads

Bengt Rutisson bengt.rutisson at oracle.com
Tue Mar 29 13:36:58 UTC 2016


Hi again,

I added some internal vm tests. Updated webrev:

http://cr.openjdk.java.net/~brutisso/8152952/webrev.01/

Diff compared to last version:

http://cr.openjdk.java.net/~brutisso/8152952/webrev.00-01.diff/

Thanks,
Bengt

On 2016-03-29 14:03, Bengt Rutisson wrote:
>
> Hi everyone,
>
> Could I have a couple of reviews for this change?
>
> http://cr.openjdk.java.net/~brutisso/8152952/webrev.00/
> https://bugs.openjdk.java.net/browse/JDK-8152952
>
> Currently if you run with UseDynamicNumberOfGCThreads you can 
> potentially get a different number of worker threads each GC. There 
> are improvements coming where we want to select a different number of 
> worker threads for individual phases. The G1GCPhaseTimes and 
> WorkerDataArray structures need to support this.
>
> The proposed patch sets all slots in the WorkerDataArray to an 
> uninitialized value and then only print any values that have actually 
> been set for that phase.
>
> The patch also extends the log message about the number for worker 
> threads to also say how many it could potentially have used. And it 
> also fixes a missing space in the level 3 and level 4 indentation.
>
> After applying this patch and running with -Xlog:gc*,phases*=trace you 
> get output like:
>
> [0,581s][info][gc,task ] GC(0) GC Workers: using 2 out of 23
> [0,588s][info][gc,phases] GC(0)   Evacuate Collection Set: 5,0ms
> [0,588s][trace][gc,phases] GC(0)       GC Worker Start (ms): Min: 
> 580,9, Avg: 580,9, Max: 580,9, Diff:  0,0
> [0,588s][trace][gc,phases,task] GC(0)                                 
> 580,9 580,9   -   -   - - -   -   -   -   -   -   -   -   -   -   -   
> -   -   -   - -   -
> [0,588s][debug][gc,phases     ] GC(0)     Ext Root Scanning (ms):   
> Min:  1,7, Avg:  1,7, Max:  1,8, Diff:  0,0, Sum:  3,5
> [0,589s][trace][gc,phases,task] GC(0)                                
> 1,8  1,7   -   -   -   - - -   -   -   -   -   -   -   -   -   -   -   
> -   -   -   -   -
> [0,589s][trace][gc,phases     ] GC(0)       Thread Roots (ms):        
> Min:  0,0, Avg:  0,7, Max:  1,5, Diff:  1,5, Sum: 1,5
> [0,589s][trace][gc,phases,task] GC(0)                                  
> 0,0  1,5   -   -   -   - -   -   -   -   -   -   -   -   -   -   -   
> -   -   -   -   -   -
>
> Thanks,
> Bengt
>
>



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