RFR (M): 8141141: Young and Old gen PLAB stats are similar in output with -XX:+PrintPLAB (original) (raw)

Thomas Schatzl thomas.schatzl at oracle.com
Tue Mar 1 17:35:37 UTC 2016


Hi all,

can I get reviews for the following change that tries to improve PLAB logging output.

In particular, instead of:

[2,245s][debug ][gc,plab] GC(33) (allocated = 1 wasted = 0 unused = 0 used = 1 undo_waste = 0 region_end_waste = 0 regions filled = 0 direct_allocated = 0 failure_used = 0 failure_waste = 0) (plab_sz = 0 desired_plab_sz = 258) [2,245s][debug ][gc,plab] GC(33) (allocated = 1 wasted = 0 unused = 0 used = 1 undo_waste = 0 region_end_waste = 0 regions filled = 0 direct_allocated = 0 failure_used = 0 failure_waste = 0) (plab_sz = 0 desired_plab_sz = 258)

The logging looks like:

[0.330s][debug][gc,plab ] GC(0) Young PLAB allocation: allocated: 1825632B, wasted: 29424B, unused: 2320B, used: 1793888B, undo waste: 0B, [0.330s][debug][gc,plab ] GC(0) Young other allocation: region end waste: 0B, regions filled: 2, direct allocated: 271520B, failure used: 0B, failure wasted: 0B [0.330s][debug][gc,plab ] GC(0) Young sizing: calculated: 358776B, actual: 358776B [0.330s][debug][gc,plab ] GC(0) Old PLAB allocation: allocated: 427248B, wasted: 592B, unused: 368584B, used: 58072B, undo waste: 0B, [0.330s][debug][gc,plab ] GC(0) Old other allocation: region end waste: 0B, regions filled: 1, direct allocated: 41704B, failure used: 0B, failure wasted: 0B [0.330s][debug][gc,plab ] GC(0) Old sizing: calculated: 11608B, actual: 11608B

I.e. with the following changes:

I think it is a big improvement.

CR: https://bugs.openjdk.java.net/browse/JDK-8141141 Webrev: http://cr.openjdk.java.net/~tschatzl/8141141/webrev/ Testing: jprt, existing plab logging test cases



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