Request for review (S): 7005808 G1: re-enable ReduceInitialCardMarks for G1
bengt.rutisson at oracle.com
Wed Sep 28 12:00:50 UTC 2011
Could I have a couple of reviews for this small change?
The code change is very small. I am just enabling the
ReduceInitialCardMarks by default for G1. The ReduceInitialCardMarks was
disabled since it caused some stability issues. The theory is that those
issues arose from the fact that there were bugs that would allocate new
objects outside the young gen. These bugs have now been fixed and we
should be able to use ReduceInitialCardMarks again.
Most of the work on this fix has been going in to testing it. I have run
the following tests:
2 x RefWorkload
1 x Full GC test suite
7 x GC test suite Dacapo2006
16 x GC test suite GCBasher
4 x JPRT - All platforms
7 x JPRT - Windows only
I choose the test distribution based on Tony's feedback that the issues
related to ReduceInitialCardMarks used to be intermittent in JPRT, and
mostly occurred on Windows, and that GCBasher and Dacapo2006 used to
have issues with it as well.
I have not seen any failures in the tests above. I also did not see any
regressions in RefWorkLoad. Unfortunately I did not see any improvement
either, but I think this change is still worth doing to make G1 behave
the same way as the other collectors wrt ReduceInitialCardMarks.
7005808 G1: re-enable ReduceInitialCardMarks for G1
This is for hs23, so I will not push it until next week.
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