Re: Tuning garbage collection
laredotornado wrote: Hi, I'm using Tomcat 6.0.26, Java 1.6 and wondering what tools/strategies you use to tune your garbage collection parameters? My main strategy is to see if I have any cripping GC problems. If not, I leave the GC to its own (or Sun's) devices. GC tuning is likely to be outdated/obseleted almost as soon as you've done it. BugBear - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: Tuning garbage collection
Google is your friend: java garbage collection log format quickly leads to http://stackoverflow.com/questions/895444/java-garbage-collection-log-messages and others Then figure out if you actually have a problem which requires any adjustment. On Jul 21, 2010, at 5:07 PM, laredotornado wrote: Hi, I'm using Tomcat 6.0.26, Java 1.6 and wondering what tools/ strategies you use to tune your garbage collection parameters? Further, does anyone know how to read entries in the garbage collection log? Entries in my log look like Desired survivor size 10944512 bytes, new threshold 1 (max 15) [PSYoungGen: 129311K-3232K(136512K)] 558882K-434085K(585920K), 0.0090900 secs] Thanks, - Dave -- View this message in context: http://old.nabble.com/Tuning-garbage-collection-tp29230790p29230790.html Sent from the Tomcat - User mailing list archive at Nabble.com. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: Tuning garbage collection
Op donderdag, 22 juli 2010 14:14 schreef paul womack pwom...@papermule.co.uk: laredotornado wrote: Hi, I'm using Tomcat 6.0.26, Java 1.6 and wondering what tools/strategies you use to tune your garbage collection parameters? My main strategy is to see if I have any cripping GC problems. If not, I leave the GC to its own (or Sun's) devices. GC tuning is likely to be outdated/obseleted almost as soon as you've done it. BugBear Just run jstat -gc on your live server for a while and check the overhead of GC. If it is to high add some memory. Ronald.
Tuning garbage collection
Hi, I'm using Tomcat 6.0.26, Java 1.6 and wondering what tools/strategies you use to tune your garbage collection parameters? Further, does anyone know how to read entries in the garbage collection log? Entries in my log look like Desired survivor size 10944512 bytes, new threshold 1 (max 15) [PSYoungGen: 129311K-3232K(136512K)] 558882K-434085K(585920K), 0.0090900 secs] Thanks, - Dave -- View this message in context: http://old.nabble.com/Tuning-garbage-collection-tp29230790p29230790.html Sent from the Tomcat - User mailing list archive at Nabble.com. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
RE: Tuning garbage collection
From: laredotornado [mailto:laredotorn...@gmail.com] Subject: Tuning garbage collection I'm using Tomcat 6.0.26, Java 1.6 and wondering what tools/strategies you use to tune your garbage collection parameters? Usually, just give the JVM as big a heap as will fit on your system with inducing paging, and let the GC algorithms figure out what to do with it. Second-guessing the GC usually ends up degrading performance, unless you're willing to do a lot of experimentation using the workloads you actually have. If you really want to play with it (and have a lot of spare time), start here: http://java.sun.com/javase/technologies/hotspot/gc/index.jsp In particular, look at this one: http://java.sun.com/javase/technologies/hotspot/gc/gc_tuning_6.html Optimizing your webapps (and data base) almost always provides greater benefit that fiddling with GC settings. Further, does anyone know how to read entries in the garbage collection log? See the above reference. Desired survivor size 10944512 bytes, new threshold 1 (max 15) That says the survivor space is just under 11 MB, and objects will be moved to the survivor space after just one collection. [PSYoungGen: 129311K-3232K(136512K)] 558882K-434085K(585920K), The young generation usage was 129 MB before the GC, 3 MB after, and the young gen could use up as much as 136 MB. The total heap usage was 558 MB, shrunk to 434 MB by the GC, and could reach a maximum of 585 MB. 0.0090900 secs] The minor GC took just over 9 milliseconds. - Chuck THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
tuning garbage collection
Good morning. I'm hoping someone has experience configuring Tomcat 4 and GC. We recently upgraded our version of Tomcat from 3 to 4, and are now experiencing periodic outages. Our problem comes when a Full GC runs. What we've seen that a Full GC is run more and more frequently to the point of running every few seconds. My site serves ~3000 JSPs per minute during peak on Solaris 8 using Java 1.4.0_04-b04 and Tomcat 4.1.31. The server.xml startup commands are -server -verbose:gc -XX:+PrintGCTimeStamps -XX:+PrintGCDetails -Xms200m -Xmx400m We tried -Xincgc which worked fine for awhile yesterday until all of a sudden all free memory on the box was used up presumably while GC ran. Research indicates that using -XX:+UseParallelGC might be an option except that it isn't supported in 1.4.0. Is upgrading Java to 1.4.2 our best solution? Any suggestions would be greatly appreciated. Thanks Ken - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: tuning garbage collection
Frankly I'd suggest moving to the latest JDK 5.0 release, 1.4.0 is a pretty old and creaking version of the JVM really. GC has undergone huge changes in Sun's JVM from 1.4.0 to their current 1.5.0_06 release. I also do wonder why you upgraded from tomcat 3 to tomcat 4. Whats wrong with tomcat 5? Mark On Wed, 2006-07-05 at 07:58 -0500, Ken Gibson wrote: Good morning. I'm hoping someone has experience configuring Tomcat 4 and GC. We recently upgraded our version of Tomcat from 3 to 4, and are now experiencing periodic outages. Our problem comes when a Full GC runs. What we've seen that a Full GC is run more and more frequently to the point of running every few seconds. My site serves ~3000 JSPs per minute during peak on Solaris 8 using Java 1.4.0_04-b04 and Tomcat 4.1.31. The server.xml startup commands are -server -verbose:gc -XX:+PrintGCTimeStamps -XX:+PrintGCDetails -Xms200m -Xmx400m We tried -Xincgc which worked fine for awhile yesterday until all of a sudden all free memory on the box was used up presumably while GC ran. Research indicates that using -XX:+UseParallelGC might be an option except that it isn't supported in 1.4.0. Is upgrading Java to 1.4.2 our best solution? Any suggestions would be greatly appreciated. Thanks Ken - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] This email has been scanned for all known viruses by the MessageLabs SkyScan service. This email has been scanned for all known viruses by the MessageLabs SkyScan service. - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
