ParNew 4x slower under 1.7 vs 1.6?

[Bernd Eckenfels]

Am 10.08.2013, 00:48 Uhr, schrieb Andrew Mulholland  
<anmulholland at expedia.com>:
> Under 1.6, we see:
> - average ParNew pause times of ~100ms
>    - with standard deviation of 0.12
> - max of ~800ms
> - cumulative total of ~11 seconds ParNew GC during the test run
>
> Under 1.7 we see:
> -  average ParNew pause times of ~440ms
>     - with standard deviation of 0.26
> - max of ~1600s
> - cumulative total of ~40 seconds PewNew GC during the test run

Sounds pretty mich like it is using less threads for the collection. Did  
you tried to run it with -XX:+PrintFlagsFinal and have a look at  
ParallelGCThreads? (CommandLineFlags shows only the ones which get  
calculated based on some compat).

Gruss
Bernd