Hi,
I don't think "Option is not recommended for use in productive
environments" is a string printed by OpenJDK. If you're using SAP's JVM
you'll have to ask SAP why they do that.
/Per
On 08/29/2018 09:59 AM, David Weeda wrote:
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/>_
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