Thanx Chuck, so with 4 tomcats I should reduce the number of gc threads to 2 per vm and with 2 tomcats to 4 for vm to have the same number of threads as with single tomcat, and hope that shorter gc runs will increase overall performance?
What do you think, is it adviseable to have multiple tomcat/jvm instance, or is the problem just that the cpu's doesn't scale? We had the machine at approx 540 requests per second before first replies started to stall, we would have expected 1000 or more for machine to be worth buying it (or exchanging other servers)... leon On 3/9/06, Caldarale, Charles R <[EMAIL PROTECTED]> wrote: > > From: Leon Rosenberg [mailto:[EMAIL PROTECTED] > > Subject: Performance tricks with multiple tomcat instances > > > > One of my assumption for relative bad performance is the gc. If I > > install 2 or 4 tomcat instances on the same machine, I assume that if > > I'm lucky the gc in the separate VMs will run not at the same time, > > therefore reducing overall 'blocking' time and increasing combined > > performance. > > A lot of this depends on what GC options you select. If you're using > parallel GC, each JVM will utilize 8 threads (by default) to do the GC > work. Since GC is CPU-intensive, this will saturate your system, but > hopefully only for a very brief period. You can limit the number of > threads with the -XX:ParallelGCThreads=<n> parameter, which defaults to > the number of CPUs if 8 or less, or 3 + 5/8 the number if more than 8. > > - 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: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
