Heap not expanding beyond -Xms512m
Hello Tomcat-oids, I'd really appreciate any help with this...Thanks in advance. We've been running performance tests against Tomcat 4.1.26 on Linux and Windows. We've tuned heap sizes to -Xms512m -Xmx1024m. Monitoring the JVM memory usage with a daemon thread calling Runtime.getRuntime().freeMemory() / totalMemory() / maxMemory(), we've noticed memory was never expanded beyond 512MB. Instead, when usage was getting close to 512MB, we could see the garbage collector kick in. We never got OOM errors. Can anyone share experiences about this? Do I have to use -Xms1024m -Xmx1024m (which seems to defeat the purpose of having ms and mx...)? Guillaume - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
RE: Heap not expanding beyond -Xms512m
This is expected behaviour. The heap will not grow if the memory required can be gained through a garbage collection. The heap will only grow if after a garbage collection it still cannot allocate the required memory or is over a certain percentage (I forget what the default is). I would suggest that you don't in fact need 512MB if your app runs fine with no OOM in 512MB. If you really want to use the full 1GB the you'll have to use -Xms as you suggested. Ta Matt -Original Message- From: Guillaume Lahitette [mailto:[EMAIL PROTECTED] Sent: 20 April 2005 13:54 To: tomcat-user@jakarta.apache.org Subject: Heap not expanding beyond -Xms512m Hello Tomcat-oids, I'd really appreciate any help with this...Thanks in advance. We've been running performance tests against Tomcat 4.1.26 on Linux and Windows. We've tuned heap sizes to -Xms512m -Xmx1024m. Monitoring the JVM memory usage with a daemon thread calling Runtime.getRuntime().freeMemory() / totalMemory() / maxMemory(), we've noticed memory was never expanded beyond 512MB. Instead, when usage was getting close to 512MB, we could see the garbage collector kick in. We never got OOM errors. Can anyone share experiences about this? Do I have to use -Xms1024m -Xmx1024m (which seems to defeat the purpose of having ms and mx...)? Guillaume - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
RE: Heap not expanding beyond -Xms512m
I agree, it's always a good idea to let the JVM do what it is supposed to do instead of creating a growing overhead. The only exception to that rule is if you think you'll reach 1024 MB, but as you say yourself, 512 seems to do fine as -Xms. btw, here is an article that goes into detail (ratio's etc.) using jvm 1.4.2 http://java.sun.com/docs/hotspot/gc1.4.2/index.html Q > -Original Message- > From: Dale, Matt [mailto:[EMAIL PROTECTED] > Sent: 20 April 2005 15:24 > To: Tomcat Users List > Subject: RE: Heap not expanding beyond -Xms512m > > > > This is expected behaviour. The heap will not grow if the > memory required can be gained through a garbage collection. > The heap will only grow if after a garbage collection it > still cannot allocate the required memory or is over a > certain percentage (I forget what the default is). > > I would suggest that you don't in fact need 512MB if your app > runs fine with no OOM in 512MB. > > If you really want to use the full 1GB the you'll have to use > -Xms as you suggested. > > Ta > Matt > > -Original Message- > From: Guillaume Lahitette [mailto:[EMAIL PROTECTED] > Sent: 20 April 2005 13:54 > To: tomcat-user@jakarta.apache.org > Subject: Heap not expanding beyond -Xms512m > > > Hello Tomcat-oids, > > I'd really appreciate any help with this...Thanks in advance. > > We've been running performance tests against Tomcat 4.1.26 on > Linux and Windows. We've tuned heap sizes to -Xms512m -Xmx1024m. > > Monitoring the JVM memory usage with a daemon thread calling > Runtime.getRuntime().freeMemory() / totalMemory() / > maxMemory(), we've noticed memory was never expanded beyond > 512MB. Instead, when usage was getting close to 512MB, we > could see the garbage collector kick in. We never got OOM errors. > > Can anyone share experiences about this? Do I have to use > -Xms1024m -Xmx1024m (which seems to defeat the purpose of > having ms and mx...)? > > Guillaume > > - > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > > - > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
RE: Heap not expanding beyond -Xms512m
Ooops, I meant -Xmx512 ;) > -Original Message- > From: Quinten Verheyen > Sent: 20 April 2005 15:32 > To: 'Tomcat Users List' > Subject: RE: Heap not expanding beyond -Xms512m > > > I agree, it's always a good idea to let the JVM do what it is > supposed to do instead of creating a growing overhead. The > only exception to that rule is if you think you'll reach 1024 > MB, but as you say yourself, 512 seems to do fine as -Xms. > > btw, here is an article that goes into detail (ratio's etc.) > using jvm 1.4.2 http://java.sun.com/docs/hotspot/gc1.4.2/index.html > > Q > > > -Original Message- > > From: Dale, Matt [mailto:[EMAIL PROTECTED] > > Sent: 20 April 2005 15:24 > > To: Tomcat Users List > > Subject: RE: Heap not expanding beyond -Xms512m > > > > > > > > This is expected behaviour. The heap will not grow if the > > memory required can be gained through a garbage collection. > > The heap will only grow if after a garbage collection it > > still cannot allocate the required memory or is over a > > certain percentage (I forget what the default is). > > > > I would suggest that you don't in fact need 512MB if your app > > runs fine with no OOM in 512MB. > > > > If you really want to use the full 1GB the you'll have to use > > -Xms as you suggested. > > > > Ta > > Matt > > > > -Original Message- > > From: Guillaume Lahitette [mailto:[EMAIL PROTECTED] > > Sent: 20 April 2005 13:54 > > To: tomcat-user@jakarta.apache.org > > Subject: Heap not expanding beyond -Xms512m > > > > > > Hello Tomcat-oids, > > > > I'd really appreciate any help with this...Thanks in advance. > > > > We've been running performance tests against Tomcat 4.1.26 on > > Linux and Windows. We've tuned heap sizes to -Xms512m -Xmx1024m. > > > > Monitoring the JVM memory usage with a daemon thread calling > > Runtime.getRuntime().freeMemory() / totalMemory() / > > maxMemory(), we've noticed memory was never expanded beyond > > 512MB. Instead, when usage was getting close to 512MB, we > > could see the garbage collector kick in. We never got OOM errors. > > > > Can anyone share experiences about this? Do I have to use > > -Xms1024m -Xmx1024m (which seems to defeat the purpose of > > having ms and mx...)? > > > > Guillaume > > > > > - > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > - > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
RE: Heap not expanding beyond -Xms512m
Quinten, Matt, Thank you for your feedback and the JVM reference. Guillaume - Original Message - From: "Quinten Verheyen" <[EMAIL PROTECTED]> To: "Tomcat Users List" Subject: RE: Heap not expanding beyond -Xms512m Date: Wed, 20 Apr 2005 15:32:12 +0200 > > I agree, it's always a good idea to let the JVM do what it is supposed to do > instead of creating a growing overhead. The only exception to that rule is if > you think you'll reach 1024 MB, but as you say yourself, 512 seems to do fine > as -Xms. > > btw, here is an article that goes into detail (ratio's etc.) using jvm 1.4.2 > http://java.sun.com/docs/hotspot/gc1.4.2/index.html > > Q > > > -Original Message- > > From: Dale, Matt [mailto:[EMAIL PROTECTED] > > Sent: 20 April 2005 15:24 > > To: Tomcat Users List > > Subject: RE: Heap not expanding beyond -Xms512m > > > > > > > > This is expected behaviour. The heap will not grow if the memory required > > can be gained through a garbage collection. The heap will only grow if > > after > > a garbage collection it still cannot allocate the required memory or is > > over > > a certain percentage (I forget what the default is). > > > > I would suggest that you don't in fact need 512MB if your app runs fine > > with > > no OOM in 512MB. > > > > If you really want to use the full 1GB the you'll have to use -Xms as you > > suggested. > > > > Ta > > Matt > > > > -Original Message- > > From: Guillaume Lahitette [mailto:[EMAIL PROTECTED] > > Sent: 20 April 2005 13:54 > > To: tomcat-user@jakarta.apache.org > > Subject: Heap not expanding beyond -Xms512m > > > > > > Hello Tomcat-oids, > > > > I'd really appreciate any help with this...Thanks in advance. > > > > We've been running performance tests against Tomcat 4.1.26 on Linux and > > Windows. We've tuned heap sizes to -Xms512m -Xmx1024m. > > > > Monitoring the JVM memory usage with a daemon thread calling > > Runtime.getRuntime().freeMemory() / totalMemory() / maxMemory(), we've > > noticed memory was never expanded beyond 512MB. Instead, when usage was > > getting close to 512MB, we could see the garbage collector kick in. We > > never > > got OOM errors. > > > > Can anyone share experiences about this? Do I have to use -Xms1024m > > -Xmx1024m (which seems to defeat the purpose of having ms and mx...)? > > > > Guillaume > > > > - > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > - > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > - > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
