Hi Charlie, This is solaris OS and there is flag argv[46]: -XX:+UseLargePages which is enabled, do you recommend to disable it.
Also per Thomas suggestion I am trying to figure out Java 1.8 compatible with our Apps and will use that in further testing. Thanks, Amit Mishra From: charlie hunt [mailto:charlie.h...@oracle.com] Sent: Saturday, February 4, 2017 00:12 To: Thomas Schatzl <thomas.scha...@oracle.com> Cc: Amit Mishra <amit.mis...@redknee.com>; hotspot-gc-use@openjdk.java.net Subject: Re: Need help on G1 GC young gen Update RS and Scan RS pause reduction > “- from one gc to another, just for these four gcs, sys time is relatively > high.” Assuming this is on Linux … perhaps double check that THP (transparent huge pages) is disabled. charlie On Feb 3, 2017, at 7:01 AM, Thomas Schatzl <thomas.scha...@oracle.com<mailto:thomas.scha...@oracle.com>> wrote: Hi Amit, On Fri, 2017-02-03 at 11:09 +0000, Amit Mishra wrote: Hi Thomas/team, I have put all parameters as per your suggestion but somehow the minor gc pauses are still haunting. Attaching GC logs. bash-3.2$ grep -i young gcstats.log.10636|cut -d, -f2|awk -F" " '{print $1}'|awk '$1 > 1' 1.1273134 1.1683221 3.5504848 5.2693987 looking at these log entries, there seems to be something going on that seems outside of VM control: - from one gc to another, just for these four gcs, sys time is relatively high. - for the last two occurrences, at least one thread is hanging in "Ext Root Scanning" for almost all of the gc time for no obvious reason. - there do not seem to be an unusually large amount of changes in the amount of work done in the particular phases that would raise immediate concerns to me. Please try to find out the source of the high sys time and maybe even what causes it. I can't help a lot in that area, but dtrace seems a good starting point as suggested earlier. I think we went through most obvious tunings now, but maybe somebody else has more ideas. I don't at this time. The jdk (7u45) you are using is also very old, so even if we find that there is something wrong with g1 in particular, I kind of doubt there are many more useful knobs to turn with that version (or even appropriate logging to find out about the actual issue). Since 7u45 release, there have been hundreds of changes that in particular improve G1 performance, so please consider upgrading to something more recent (at least latest 8u, preferably to me some test runs with 9ea). Upgrading alone might already help. Thanks, Thomas _______________________________________________ hotspot-gc-use mailing list hotspot-gc-use@openjdk.java.net<mailto:hotspot-gc-use@openjdk.java.net> http://mail.openjdk.java.net/mailman/listinfo/hotspot-gc-use
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