Great updates. Thanks for keeping us all in the loop!
On Thu, Oct 22, 2020 at 7:43 PM Wei <weiwan...@gmail.com> wrote: > > Hi Shawn, > > I.m circling back with some new findings with our 2 NUMA issue. After a > few iterations, we do see improvement with the useNUMA flag and other JVM > setting changes. Here are the current settings, with Java 11: > > -XX:+UseNUMA > > -XX:+UseG1GC > > -XX:+AlwaysPreTouch > > -XX:+UseTLAB > > -XX:G1MaxNewSizePercent=20 > > -XX:MaxGCPauseMillis=150 > > -XX:+DisableExplicitGC > > -XX:+DoEscapeAnalysis > > -XX:+ParallelRefProcEnabled > > -XX:+UnlockDiagnosticVMOptions > > -XX:+UnlockExperimentalVMOptions > > > Compared to previous Java 8 + CMS on 2 NUMA servers, P99 latency has > improved over 20%. > > > Thanks, > > Wei > > > > > On Mon, Sep 28, 2020 at 4:02 PM Shawn Heisey <apa...@elyograg.org> wrote: > > > On 9/28/2020 12:17 PM, Wei wrote: > > > Thanks Shawn. Looks like Java 11 is the way to go with -XX:+UseNUMA. Do > > you > > > see any backward compatibility issue for Solr 8 with Java 11? Can we run > > > Solr 8 built with JDK 8 in Java 11 JRE, or need to rebuild solr with Java > > > 11 JDK? > > > > I do not know of any problems running the binary release of Solr 8 > > (which is most likely built with the Java 8 JDK) with a newer release > > like Java 11 or higher. > > > > I think Sun was really burned by such problems cropping up in the days > > of Java 5 and 6, and their developers have worked really hard to make > > sure that never happens again. > > > > If you're running Java 11, you will need to pick a different garbage > > collector if you expect the NUMA flag to function. The most recent > > releases of Solr are defaulting to G1GC, which as previously mentioned, > > did not gain NUMA optimizations until Java 14. > > > > It is not clear to me whether the NUMA optimizations will work with any > > collector other than Parallel until Java 14. You would need to check > > Java documentation carefully or ask someone involved with development of > > Java. > > > > If you do see an improvement using the NUMA flag with Java 11, please > > let us know exactly what options Solr was started with. > > > > Thanks, > > Shawn > >
