Good Afternoon, I have set the parameter in our development system however the following message is now displayed in the start-up log. J Option is not recommended for use in productive environments: -XX:+UseNUMA
Regards, David Weeda SAP Technical Architect From: sangheon....@oracle.com <sangheon....@oracle.com> Sent: Wednesday, 29 August 2018 6:57 AM To: David Weeda <david.we...@det.nsw.edu.au>; hotspot-gc-use@openjdk.java.net Cc: Jag Inturi <jag.int...@det.nsw.edu.au> Subject: Re: -XX:+UseNUMA in conjunction with -XX:+UseG1GC Hi David, On 8/26/18 11:18 PM, David Weeda wrote: Hello, We are upgrading our SAP Java Application servers to use SAP JVM 8.1 Patch Collection 39. This release integrates updates from Oracle JDK 8u172 The GC shall be switched from -XX:+UseConcMarkSweepGC to -XX:+UseG1GC. On the following website:- https://docs.oracle.com/javase/8/docs/technotes/guides/vm/performance-enhancements-7.html#numa There is a note on NUMA Collector Enhancements for the Parallel Scavenger garbage collector. Are the subsequent collectors, namely the G1 garbage collector also NUMA aware? No, G1 is not NUMA aware. Only Parallel GC(-XX:+UseParallelGC) has NUMA awareness. Is it default? If you are asking UseNUMA option is by default for G1GC, no UseNUMA is always false by default. May I use the -XX:+UseNUMA flag with -XX:+UseG1GC? Yes, you can use +UseNUMA with +UseG1GC. G1 algorithm is not NUMA aware, but with UseNUMA enabled, we can get NUMA interleaving. i.e. Interleave memory across NUMA nodes if possible and this would give some benefits on NUMA system. FYI, UseNUMAInterleaving(false by default) command-line option will be automatically enabled if UseNUMA is enabled. HTH, Sangheon Regards, David Weeda SAP Technical Architect | Enterprise Systems | Information Technology Directorate Level 11, 8 Central Ave | Eveleigh NSW 2015 | |*:+61 (0)4 8822 0280 | *: david.we...@det.nsw.edu.au<mailto:david.we...@det.nsw.edu.au> | www.dec.nsw.gov.au<http://www.dec.nsw.gov.au/> [cid:image003.png@01D0B4D4.6A6EFF30] ********************************************************************** This message is intended for the addressee named and may contain privileged information or confidential information or both. If you are not the intended recipient please delete it and notify the sender. ********************************************************************** _______________________________________________ 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 ********************************************************************** This message is intended for the addressee named and may contain privileged information or confidential information or both. If you are not the intended recipient please delete it and notify the sender. **********************************************************************
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