AppletTalk.com Java discussions newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Performance Issues with Multiple JVMs          AppletTalk.com Forum Index -> comp.lang.java.developer View previous topic :: View next topic   Author Message Amit M Bhosle Guest Posted: Thu Apr 22, 2004 10:24 am    Post subject: Performance Issues with Multiple JVMs Hi: am facing some performance issues in a scenario where my program launches multiple JVMs (the Runtime.exec(..) stuff).. and was wondering if someone here has been in similar situation.. the issue is that when i launch, say 5 JVMs, all of them doing similar but different jobs, 3 of them finish their job quite early, while the remaining 2 take time more than double the time taken by the other 3 !! and this happens even when the CPU is being used by almost exclusively by these 2 processes. any suggestions/pointers would be highly appreciated.. cheers.. AMB Back to top Jeff Schwab Guest Posted: Thu Apr 22, 2004 11:47 am    Post subject: Re: Performance Issues with Multiple JVMs Amit M Bhosle wrote: Quote: Hi: am facing some performance issues in a scenario where my program launches multiple JVMs (the Runtime.exec(..) stuff).. and was wondering if someone here has been in similar situation.. the issue is that when i launch, say 5 JVMs, all of them doing similar but different jobs, 3 of them finish their job quite early, while the remaining 2 take time more than double the time taken by the other 3 !! and this happens even when the CPU is being used by almost exclusively by these 2 processes. any suggestions/pointers would be highly appreciated.. Is your system running out of memory, such that two of the JVM's are getting swapped to disk? Back to top Chris Guest Posted: Thu Apr 22, 2004 3:49 pm    Post subject: Re: Performance Issues with Multiple JVMs not sure what you're doing.. as far as tasks but here's a thought i have: anyway to write a controller application that you just launch once, and then it spawns 5 threads, 1 for each job task ? that will reduce the 5 jvms into one. and should speed up your multi-parallel processing. [email]bhosle (AT) cs (DOT) ucsb.edu[/email] (Amit M Bhosle) wrote in message news:<2ebcb646.0404220224.5a89da3d (AT) posting (DOT) google.com>... Quote: Hi: am facing some performance issues in a scenario where my program launches multiple JVMs (the Runtime.exec(..) stuff).. and was wondering if someone here has been in similar situation.. the issue is that when i launch, say 5 JVMs, all of them doing similar but different jobs, 3 of them finish their job quite early, while the remaining 2 take time more than double the time taken by the other 3 !! and this happens even when the CPU is being used by almost exclusively by these 2 processes. any suggestions/pointers would be highly appreciated.. cheers.. AMB Back to top Amit M Bhosle Guest Posted: Fri Apr 23, 2004 8:01 am    Post subject: Re: Performance Issues with Multiple JVMs Chris, my main process (the jvm i launch manually) spawns 5 new processes (not threads.. the tasks r computation/memory intensive, which is why i decided to check two implementations - multiple threads and multiple processes.. the thread approach is still unimplemented).. Jeff, none of the processes throws an "Out of Memory" error.. and given sufficient time, all of them do finish their task.. also, i checked the memory usage shown by the "Task Manager", but the memory used by the parent JVM and the 2 last JVMs is only about 300M, which leaves about 200M free in the system.. - AMB [email]cbroussard (AT) liquiddatainc (DOT) com[/email] (Chris) wrote in message news:<89b6b185.0404220749.4346d5ad (AT) posting (DOT) google.com>... Quote: not sure what you're doing.. as far as tasks but here's a thought i have: anyway to write a controller application that you just launch once, and then it spawns 5 threads, 1 for each job task ? that will reduce the 5 jvms into one. and should speed up your multi-parallel processing. [email]bhosle (AT) cs (DOT) ucsb.edu[/email] (Amit M Bhosle) wrote in message news:<2ebcb646.0404220224.5a89da3d (AT) posting (DOT) google.com>... Hi: am facing some performance issues in a scenario where my program launches multiple JVMs (the Runtime.exec(..) stuff).. and was wondering if someone here has been in similar situation.. the issue is that when i launch, say 5 JVMs, all of them doing similar but different jobs, 3 of them finish their job quite early, while the remaining 2 take time more than double the time taken by the other 3 !! and this happens even when the CPU is being used by almost exclusively by these 2 processes. any suggestions/pointers would be highly appreciated.. cheers.. AMB Back to top Jeff Schwab Guest Posted: Fri Apr 23, 2004 2:53 pm    Post subject: Re: Performance Issues with Multiple JVMs Please don't top-post. Amit M Bhosle wrote: Quote: Jeff, none of the processes throws an "Out of Memory" error.. and given sufficient time, all of them do finish their task.. also, i checked the memory usage shown by the "Task Manager", but the memory used by the parent JVM and the 2 last JVMs is only about 300M, which leaves about 200M free in the system.. I wouldn't expect an "Out of Memory" error if there were plentiful swap space. Are you sure the remaining 200M are free, or did you just subtract 300 from 500? Back to top Mark A. Washburn Guest Posted: Fri Apr 23, 2004 4:43 pm    Post subject: Re: Performance Issues with Multiple JVMs [email]bhosle (AT) cs (DOT) ucsb.edu[/email] (Amit M Bhosle) wrote in message news:<2ebcb646.0404222306.354c10b9 (AT) posting (DOT) google.com>... Quote: Chris, my main process (the jvm i launch manually) spawns 5 new processes (not threads.. the tasks r computation/memory intensive, which is why i decided to check two implementations - multiple threads and multiple processes.. the thread approach is still unimplemented).. Jeff, none of the processes throws an "Out of Memory" error.. and given sufficient time, all of them do finish their task.. also, i checked the memory usage shown by the "Task Manager", but the memory used by the parent JVM and the 2 last JVMs is only about 300M, which leaves about 200M free in the system.. - AMB I'm not sure exactly how the problem is defined, however, if you must use multiple processes then have you tried Echinda? http://sourceforge.net/projects/echidna/ There are a few others projects for executing multiple processes within a single JVM, I've had good results with both JDistro ( in Warf mode) and JSH ( Java Shell, uses a modified Echidna ) JDistro http://www.jdistro.com/ JSH http://sourceforge.net/projects/jsh/ maw Back to top Amit M Bhosle Guest Posted: Mon Apr 26, 2004 6:58 am    Post subject: Re: Performance Issues with Multiple JVMs [email]Reply7471859353 (AT) wmconnect (DOT) com[/email] (Mark A. Washburn) wrote in message news:<ce0bd25d.0404230843.67bdd50f (AT) posting (DOT) google.com>... Quote: bhosle (AT) cs (DOT) ucsb.edu (Amit M Bhosle) wrote in message news:<2ebcb646.0404222306.354c10b9 (AT) posting (DOT) google.com>... Chris, my main process (the jvm i launch manually) spawns 5 new processes (not threads.. the tasks r computation/memory intensive, which is why i decided to check two implementations - multiple threads and multiple processes.. the thread approach is still unimplemented).. Jeff, none of the processes throws an "Out of Memory" error.. and given sufficient time, all of them do finish their task.. also, i checked the memory usage shown by the "Task Manager", but the memory used by the parent JVM and the 2 last JVMs is only about 300M, which leaves about 200M free in the system.. - AMB I'm not sure exactly how the problem is defined, however, if you must use multiple processes then have you tried Echinda? http://sourceforge.net/projects/echidna/ There are a few others projects for executing multiple processes within a single JVM, I've had good results with both JDistro ( in Warf mode) and JSH ( Java Shell, uses a modified Echidna ) JDistro http://www.jdistro.com/ JSH http://sourceforge.net/projects/jsh/ maw thanx for the pointers.. will look at these.. Jeff, yes, i did subtract 300 from 500 when i said that there's still 200M free.. and the reason was that when i checked the "Tast manager", that's all other processes except for the JVMs consumed negligible memory.. while the running JVMs' usage adds up to about 300.. 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