RFR (L): 8058354: SPECjvm2008-Derby -2.7% performance regression on Solaris-X64 starting with 9-b29

Thomas Schatzl thomas.schatzl at oracle.com
Tue Feb 3 10:27:02 UTC 2015


Hi Jon,

  thanks for the comments. I incorporated all of them in the latest
webrev at

http://cr.openjdk.java.net/~tschatzl/8058354/webrev.1/ (full)
http://cr.openjdk.java.net/~tschatzl/8058354/webrev.0_to_1/ (diff)

There is also a small change to the WhiteBox class that I originally
forgot to ask reviews for because it is tracked in the root directory:

http://cr.openjdk.java.net/~tschatzl/8058354/webrev.hs-gc.1/

One comment further down.

On Fri, 2015-01-30 at 14:55 -0800, Jon Masamitsu wrote:
> Thomas,
> 
> http://cr.openjdk.java.net/~tschatzl/8058354/webrev/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp.frames.html
> 
> Please verify that this should be a call to the _unaligned version.
> 
> > 1840   size_t const commit_size = os::page_size_for_region_unaligned(size, 1);

Yes. It ensures that as soon as the given size is larger than a large
page, try to use large pages (if they are enabled).

This is the same behavior as in 9b28.

If we used os::page_size_for_region_aligned(), we would only try to use
large pages in case the given size is exactly a multiple of large page
size.

Thanks,
  Thomas




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