RFR (M): 8141141: Young and Old gen PLAB stats are similar in output with -XX:+PrintPLAB (original) (raw)
Bengt Rutisson bengt.rutisson at oracle.com
Wed Mar 2 09:37:52 UTC 2016
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Hi Thomas,
Looks good. Nice improvement to the logging!
The code duplication between G1EvacStats and PLABStats is a bit unfortunate, but it is probably outside the scope of your change to do anything about that.
Thanks, Bengt
On 2016-03-01 18:35, Thomas Schatzl wrote:
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 undowaste = 0 regionendwaste = 0 regions filled = 0 directallocated = 0 failureused = 0 failurewaste = 0) (plabsz = 0 desiredplabsz = 258) [2,245s][debug ][gc,plab] GC(33) (allocated = 1 wasted = 0 unused = 0 used = 1 undowaste = 0 regionendwaste = 0 regions filled = 0 directallocated = 0 failureused = 0 failurewaste = 0) (plabsz = 0 desiredplabsz = 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: - add "Young"/"Old" identifier to show "generation" - split information into multiple lines; the "other allocation" and "sizing" are optional. "other allocation" is only printed when using G1, "sizing" only when ResizePLAB is enabled - values are in bytes now (with units), not heapwords 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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