Hi Bernd,
On Thu, Aug 1, 2013 at 4:07 AM, Bernd Fehling < bernd.fehl...@uni-bielefeld.de> wrote: > Yes, UseNuma is only for Parallel Scavenger garbage collector and only > for Solaris 9 and higher and Linux kernel 2.6.19 and glibc 2.6.1. > And it performs with 64-bit better than 32-bit. > So no effects for G1. > > With standard applications CMS is very slightly better than G1 but > when it comes to huge heaps with high fragmentation G1 is better than CMS. > The documentation says, one benefit of G1 is if the application has > more than 50% of the Java heap occupied with live data. > Could you rephrase this bit please? I don't understand it, but I think it is important concern. So first step is to size the heap that you have about 3/4 of the heap > occupied with live data and then go on comparing CMS against G1. > Thanks, roman > Otherwise G1 and CMS are about same or as I said CMS might be slightly > better. > > Also, either turn swap off or also record vmstat. This should make sure > that during a garbage collection no other system activity, like moving > JVM heap to swap in background, is distorting your measurements. > > > Bernd > > > Am 31.07.2013 05:01, schrieb Shawn Heisey: > > On 7/30/2013 6:59 PM, Roman Chyla wrote: > >> I have been wanting some tools for measuring performance of SOLR, > similar > >> to Mike McCandles' lucene benchmark. > >> > >> so yet another monitor was born, is described here: > >> http://29min.wordpress.com/2013/07/31/measuring-solr-query-performance/ > >> > >> I tested it on the problem of garbage collectors (see the blogs for > >> details) and so far I can't conclude whether highly customized G1 is > better > >> than highly customized CMS, but I think interesting details can be seen > >> there. > >> > >> Hope this helps someone, and of course, feel free to improve the tool > and > >> share! > > > > I have a CMS config that's even more tuned than before, and it has made > > things MUCH better. This new config is inspired by more info that I got > > on IRC: > > > > http://wiki.apache.org/solr/ShawnHeisey#GC_Tuning > > > > The G1 customizations in your blog post don't look like they are really > > G1-specific - they may be useful with CMS as well. This statement also > > applies to some of the CMS parameters, so I would use those with G1 as > > well for any testing. > > > > UseNUMA looks interesting for machines that actually are NUMA. All the > > information that I can find says it is only for the throughput > > (parallel) collector, so it's probably not doing anything for G1. > > > > The pause parameters you've got for G1 are targets only. It will *try* > > to stick within those parameters, but if a collection requires more than > > 50 milliseconds or has to happen more often than once a second, the > > collector will ignore what you have told it. > > > > Thanks, > > Shawn > > > >
