tag:blogger.com,1999:blog-7735872642513631302.post8141846480622372985..comments2023-07-15T17:54:51.492+01:00Comments on Alexey Ragozin: HotSpot JVM garbage collection options cheat sheet (v2)Alexey Ragozinhttp://www.blogger.com/profile/13720493857045012756noreply@blogger.comBlogger18125tag:blogger.com,1999:blog-7735872642513631302.post-17734265751144646142016-03-18T19:26:29.860+00:002016-03-18T19:26:29.860+00:00It seems this article is getting obsolete as there...It seems this article is getting obsolete as there were more options added to JDK8<br /><br />https://blogs.oracle.com/poonam/entry/about_g1_garbage_collector_permanentAnonymoushttps://www.blogger.com/profile/03077081022791929584noreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-63206698830125973562015-04-21T08:37:19.299+01:002015-04-21T08:37:19.299+01:00Hi,
I am using -XX:NewSize=200m in my attempt to i...Hi,<br />I am using -XX:NewSize=200m in my attempt to implement CMS collector. But the option is not recognized.<br />I use the following params.<br />-XX:NewSize=200m <br />-XX:+UseConcMarkSweepGC <br />-XX:+UseParNewGC<br /><br />But I get error as:<br />2015-04-20 22:24:28 Commons Daemon procrun stderr initialized<br />Unrecognized VM option 'NewSize=200m '<br /><br />I am using Java HotSpot(TM) 64-Bit Server VM 1.7.0_03 Oracle CorporationAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-8193286088284294092013-07-22T17:35:39.327+01:002013-07-22T17:35:39.327+01:00Hi Alexey,
I am getting "permgen out of memo...Hi Alexey,<br /><br />I am getting "permgen out of memory". In Jave 5 this was fixed with the options "XX:+CMSClassUnloadingEnabled XX:+CMSPermGenSweepingEnabled".<br /><br />Do you know if XX:+UseG1GC will perform the same function in java 6 (release 43)?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-14888918551697681162013-07-16T14:31:49.317+01:002013-07-16T14:31:49.317+01:00Hi Maxim,
GC tuning strategy really depends on nu...Hi Maxim,<br /><br />GC tuning strategy really depends on numbers (capacity, number of evictions per second, memory you a willing to waste).<br /><br />Question you have posted in stackoverflow is too generic to be answered properly.<br /><br />Generic guidelines for tuning CMS could be found on this blog http://blog.ragozin.info/2011/07/gc-check-list-for-data-grid-nodes.htmlAlexey Ragozinhttps://www.blogger.com/profile/13720493857045012756noreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-78900211700030669612013-07-15T14:50:43.046+01:002013-07-15T14:50:43.046+01:00Hello Alexey,
I'd like to thank you for the g...Hello Alexey,<br /><br />I'd like to thank you for the good articles (not only this one).<br /><br />Could you please also advice something about the following post:<br /><br />http://stackoverflow.com/questions/17654964/gc-pause-tuning-of-long-fifo-queue-applicationAnonymoushttps://www.blogger.com/profile/03726715173274195118noreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-18548455482583124882013-04-30T06:45:49.747+01:002013-04-30T06:45:49.747+01:00Good article!Good article!孤独的怪兽https://www.blogger.com/profile/03129423064850111017noreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-48733135855165367212012-09-30T00:43:19.450+01:002012-09-30T00:43:19.450+01:00Since 7U2 HS supports rotating GC logfiles:
java ...Since 7U2 HS supports rotating GC logfiles:<br /><br />java -Xloggc:app.vgc -XX:+PrintGCDetails<br /> -XX:GCLogFileSize=10M -XX:NumberOfGCLogFiles=10<br /> -XX:+UseGCLogFileRotation<br /> -XX:+PrintGCDateStamps -XX:-PrintGCTimeStamps<br /><br />See also my german blog: http://itblog.eckenfels.net/archives/493-Oracle-Java-SE-hotspot-GC-Logfile-rotation.htmlBernd Eckenfelshttp://itblog.eckenfels.netnoreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-76177490672363043472012-09-05T22:25:39.999+01:002012-09-05T22:25:39.999+01:001.5 is pretty old now, I doubt it supports this fe...1.5 is pretty old now, I doubt it supports this featureAlexey Ragozinhttps://www.blogger.com/profile/13720493857045012756noreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-67937577854685902362012-09-05T13:56:45.392+01:002012-09-05T13:56:45.392+01:00Hi, I am trying to use the option -XX:ConcGCThread...Hi, I am trying to use the option -XX:ConcGCThreads=2 for CMS but my JVM did not recognize. I am using the below version.<br /><br />java version "1.5.0_11"<br />Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_11-b03)<br />Java HotSpot(TM) Server VM (build 1.5.0_11-b03, mixed mode)<br /><br />pls advise if we have alternate option which can perform the same action.<br /><br />regards<br /><br />AzumAzumnoreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-16593522534881788802012-05-16T15:14:57.223+01:002012-05-16T15:14:57.223+01:00Indeed -Xss interpreted as value in byte, but -XX:...Indeed -Xss interpreted as value in byte, but -XX:ThreadStackSize=256k as value in Kbytes (256k is translated to 256m).<br />Thanks for pointing this outAlexey Ragozinhttps://www.blogger.com/profile/13720493857045012756noreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-73864543624134252162012-05-16T12:07:22.033+01:002012-05-16T12:07:22.033+01:00Hi, there is a small mistake in the list regarding...Hi, there is a small mistake in the list regarding -XX:ThreadStackSize=256k should be changed to XX:ThreadStackSize=256 (without the 'k')<br /><br />Otherwise the JVM fails to start. Not sure whether -Xss is ok with the 'k'Artiom Gourevitch (Art)https://www.blogger.com/profile/03165020593655358348noreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-31146172780550718782012-04-30T14:21:43.839+01:002012-04-30T14:21:43.839+01:00My apologies ! Indeed, I didn't notice the lit...My apologies ! Indeed, I didn't notice the little, but very important difference (+ is not - of course !). Your options are OK.<br />Best regards,<br />MichelAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-61212550485366299512012-04-30T13:25:26.826+01:002012-04-30T13:25:26.826+01:00Notice difference between -XX:- and -XX:+ options....Notice difference between -XX:- and -XX:+ options. -XX:-UseParNewGC forces ParNew to be disabled, so DefNew will be used.Alexey Ragozinhttps://www.blogger.com/profile/13720493857045012756noreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-47172287157007324072012-04-30T10:32:13.283+01:002012-04-30T10:32:13.283+01:00Hello Alexey,
I wonder if there isn't à littl...Hello Alexey,<br /><br />I wonder if there isn't à little mistake in the array of the Hotspot collectors options. For Serial (DefNew) and Concurrent Mark Sweep, you have indicated the following options to activate this mode :<br />-XX:+UseConcMarkSweepGC and -XX:-UseParNewGC<br />Is UseParNewGC correct ? IMHO, this is rather the option for the ParNew mode, no ?<br />Thks,<br />MichelAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-40203399052876154512012-02-02T18:07:35.674+00:002012-02-02T18:07:35.674+00:00Very helpful list. Would be nice if most current ...Very helpful list. Would be nice if most current default values could be included where they are known. <br />Thanks,<br />AndrewAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-42993637328461087852011-12-25T18:11:38.656+00:002011-12-25T18:11:38.656+00:00Hi Guy,
I'm not aware of any such optionsfor G...Hi Guy,<br />I'm not aware of any such optionsfor G1.<br />You probably should try to ask on hotspot-gc-use@openjdk.java.net mailing list.<br /><br />Regards,<br />AlexeyAlexey Ragozinhttps://www.blogger.com/profile/13720493857045012756noreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-78110943043116266002011-12-25T14:12:55.062+00:002011-12-25T14:12:55.062+00:00Thanks for the list! We started to test with G1 an...Thanks for the list! We started to test with G1 and couldn't find a way (as we have CMS) to control when it starts. <br />Meaning, we don't want it to wait until it uses 80% of the memory (as we seen happen) since we only really use 50% of the memory.<br />Do you know if there's a parameter similar to the "-XX:CMSInitiatingOccupancyFraction=60 -XX:+UseCMSInitiatingOccupancyOnly"<br /><br />ThanksGuy Korlandhttps://www.blogger.com/profile/16851745576455431979noreply@blogger.comtag:blogger.com,1999:blog-7735872642513631302.post-74240138363740879572011-11-20T04:50:06.075+00:002011-11-20T04:50:06.075+00:00Very good list, Main problem with JVM options is t...Very good list, Main problem with JVM options is that they are lot and you can't remember all of those so having some of them is good idea. I have also shared Some <a href="http://javarevisited.blogspot.com/2011/11/hotspot-jvm-options-java-examples.html" rel="nofollow">important memory and gc JVM options</a> you may find worth reading.javin paulhttps://www.blogger.com/profile/15028902221295732276noreply@blogger.com