GC performance regression between 7u11->7u45?

[Srinivas Ramakrishna]

Thanks Jon.

intel/linux, c2, ps gc.

Will turn off adaptive size policy. Survivor space sizing seems to be
different causing more promotion, at a high level.

Haven't tried to narrow down to VM or JDK yet, but survivor size diffs may
be key, so yr suggestion to turn off adaptive size may be the thing.

Also need to get more data to see how reproducible it is with workload etc.

thanks!
-- ramki



On Thu, Nov 14, 2013 at 2:57 PM, Jon Masamitsu <jon.masamitsu at oracle.com>wrote:

>  Ramki,
>
> I don't think we've seen such a regression.  Fix the heap size and
> turn off UseAdaptivesizePolicy.
>
> What platform?
>
> Jon
>
>
> On 11/14/13 1:46 PM, Srinivas Ramakrishna wrote:
>
>
>  Is anyone, especially the perf and gc teams inside Oracle, aware of any
> parallel young (PS) gc performance regressions
>  from 7u11 to 7u45?
>
>  I am seeing some 20-30% regression in minor gc times (and a lesser
> increase in promotion volume per scavenge),
>  on some random testing of a largish application. Haven't dug into the
> details yet, but wondered if this was noted
> on any of the Oracle perf/gc or community perf/gc radars and if there's
> any guidance available.
>
>  As I delve deeper the nature of this apparent GC regression, which I just
> became aware of, I'll post more.
>
> thanks for any help!
>  -- ramki
>
>
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