What influences young generation pause times?

Jon Masamitsu jon.masamitsu at oracle.com
Tue Apr 20 13:39:34 PDT 2010


On 04/20/10 13:30, Matt Khan wrote:
>
> >> You might need a VM with this fix. 6782663: Data produced by 
> PrintGCApplicationConcurrentTime and PrintGCApplicationStoppedTime is 
> not accurate
> OK so that's the early access for 6u21 by the looks of it. I'll repeat 
> a run on that JVM (and with the safepoint stats).
>
> >> If the log doesn't show a [GC...] line at a safepoint, then there 
> is not GC activity during it
> does this mean that the actual time stopped due to GC is the one 
> immediately after the GC line? 

As you can see more than GC can contribute to a STW so the "time 
stopped" might include
other times that don't log any message.   The GC entries in the log 
print their own times.
>
>
> >> You could use -XX:+PrintSafepointStatistics etc. to figure these out.
> which other flags should I look at?
I don't know of any others.
>
> Cheers
> Matt
>
> Matt Khan
> --------------------------------------------------
> GFFX Auto Trading
> Deutsche Bank, London
>
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