[rvm-research] What is stressTestGC

[Dingwen Yuan]

Hi All,

I looked at the causes of gc and noticed that there was a "stressTestGC" which seemed to require a gc after every 524288 pages was committed by the mutator. I don't know what's the use of that. Could anyone explain this to me?

source:
protected boolean collectionRequired(boolean spaceFull) {
    boolean stressForceGC = stressTestGCRequired();
    boolean heapFull = getPagesReserved() > getTotalPages();
    return spaceFull || stressForceGC || heapFull;
  }

Thanks.

regards,

Dingwen

TU Darmstadt

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[Steve Blackburn]

Hi Dingwen,

This mechanism allows us to stress the GC, if we wish.   If we make  
the stress interval very small (the GC frequency very high), we can  
stress the GC infrastructure.   In particular, we can force many more  
GCs to occur than normal, thereby testing the compiler-generated GC  
maps more efficiently than if we just ran the system normally.

So, in short, it is a debugging/testing tool.

--Steve

On 14/08/2009, at 6:08 PM, Dingwen Yuan wrote:

> Hi All,
>
> I looked at the causes of gc and noticed that there was a  
> "stressTestGC" which seemed to require a gc after every 524288 pages  
> was committed by the mutator. I don't know what's the use of that.  
> Could anyone explain this to me?
>
> source:
> protected boolean collectionRequired(boolean spaceFull) {
>     boolean stressForceGC = stressTestGCRequired();
>     boolean heapFull = getPagesReserved() > getTotalPages();
>     return spaceFull || stressForceGC || heapFull;
>   }
>
> Thanks.
>
> regards,
>
> Dingwen
>
> TU Darmstadt
> ------------------------------------------------------------------------------
> Let Crystal Reports handle the reporting - Free Crystal Reports 2008  
> 30-Day
> trial. Simplify your report design, integration and deployment - and  
> focus on
> what you do best, core application coding. Discover what's new with
> Crystal Reports now.  http://p.sf.net/sfu/bobj-july_______________________________________________
> Jikesrvm-researchers mailing list
> Jikesrvm-researchers@...
> https://lists.sourceforge.net/lists/listinfo/jikesrvm-researchers

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[Dingwen Yuan]

Hi Steve,

Oh, I see. Thanks.

regards,

Dingwen

2009/8/14 Steve Blackburn <Steve.Blackburn@...>

Hi Dingwen,

This mechanism allows us to stress the GC, if we wish.   If we make
the stress interval very small (the GC frequency very high), we can
stress the GC infrastructure.   In particular, we can force many more
GCs to occur than normal, thereby testing the compiler-generated GC
maps more efficiently than if we just ran the system normally.

So, in short, it is a debugging/testing tool.

--Steve

On 14/08/2009, at 6:08 PM, Dingwen Yuan wrote:

> Hi All,
>
> I looked at the causes of gc and noticed that there was a
> "stressTestGC" which seemed to require a gc after every 524288 pages
> was committed by the mutator. I don't know what's the use of that.
> Could anyone explain this to me?
>
> source:
> protected boolean collectionRequired(boolean spaceFull) {
>     boolean stressForceGC = stressTestGCRequired();
>     boolean heapFull = getPagesReserved() > getTotalPages();
>     return spaceFull || stressForceGC || heapFull;
>   }
>
> Thanks.
>
> regards,
>
> Dingwen
>
> TU Darmstadt

> ------------------------------------------------------------------------------
> Let Crystal Reports handle the reporting - Free Crystal Reports 2008
> 30-Day
> trial. Simplify your report design, integration and deployment - and
> focus on
> what you do best, core application coding. Discover what's new with
> Crystal Reports now.  http://p.sf.net/sfu/bobj-july_______________________________________________
> Jikesrvm-researchers mailing list
> Jikesrvm-researchers@...
> https://lists.sourceforge.net/lists/listinfo/jikesrvm-researchers


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