RFR(S): 6818524: G1: use ergonomic resizing of PLABs
john.cuthbertson at oracle.com
Wed Aug 1 14:11:37 PDT 2012
Can I have a couple of volunteers review the changes for this CR? The
webrev can be found at:
http://cr.openjdk.java.net/~johnc/6818524/webrev.0/. These changes have
been contributed by Brandon Mitchell (at Twitter).
PLABStats instances are now employed in G1 to record information about
old and young PLABs, and they are then used to adjust the PLAB sizes for
the next GC. As a result the ResizePLAB flag is now being observed by
G1. The previous behavior (and PLAB sizes) can be obtained by specifying
With these changes I see just over a net 1% performance gain, on our
reference workload, when running with G1.
GC test suite with and without ResizePLAB and PrintPLAB enabled to
observe the changes in PLAB sizes; reference workload on multiple
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