> -----Original Message----- > From: Mark Thomas [mailto:ma...@apache.org] > Sent: Saturday, December 14, 2013 9:06 AM > To: Tomcat Users List > Subject: Re: high CPU usage with NIO and 1000+ websockets on Tomcat 7.0.49? > > On 13/12/2013 13:12, Bob DeRemer wrote: > > We have been profiling this in YourKit and as we increase the number > > of websockets, naturally we see the CPU utilization increase. The > > concern is that we're seeing this at what seems to be a fairly low > > number of websockets. The YourKit profiling showed 41% of the time > > being spent in the following code. My apologies for the formatting. > > I can provide an attachment out-of-band if it would be helpful. > > I've seen similar figures from YourKit when testing with just a single > connection. There does seem to be a lot of time spent in the NIO Poller code. > > When I looked at it last time nothing immediately obvious jumped out at me in > terms of something that could be changed to improve things. It needs some > more time spent on a deeper analysis. That is on my TODO list. If any NIO > experts want to take a look and make some suggestions that would be great. > > As an aside, as much as I like YourKit, you do have to be careful (as you do > with > any profiler) when stress testing that the profiler isn't distorting the > results. I > have been led down the wrong path a few times when I wasn't careful enough. >
I have noticed about a 20% reduction in performance using Yourkit in it's least intrusive mode. Thanks for the input and suggestions. If I find out anything additional, I'll post it. Thx, bob > Mark > > --------------------------------------------------------------------- > 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
