So, I take it you've monitored the machine and made sure there are no other processes using up CPU/IO Bandwidth?
George Sexton MH Software, Inc. http://www.mhsoftware.com/ Voice: 303 438 9585 > -----Original Message----- > From: neilgoldsmith [mailto:ne...@avaya.com] > Sent: Friday, August 21, 2009 9:11 AM > To: users@tomcat.apache.org > Subject: Tracking down a Tomcat slowdown > > > We have a servlet that handles incoming voice calls at customer > locations, so > you can have bursts of busy time (much like web traffic). A customer > of > ours has been running this servlet (24/7) for a few months and can go > weeks > at a time with no problems, but periodically they will experience a big > slowdown on the app server which does eventually recover (slows down > for > maybe an hour). We had them increase their maxThreads from 150 to 300 > and > increase the heap size: > > (their current server.xml settings) > <Connector port="8080" maxHttpHeaderSize="8192" > maxThreads="300" minSpareThreads="25" maxSpareThreads="75" > enableLookups="false" redirectPort="8443" acceptCount="100" > connectionTimeout="20000" disableUploadTimeout="true" /> > > JAVA_OPTS=%JAVA_OPTS% -Djava.util.logging.manager=org.apache.juli.Cla > ssLoaderLogManager > - > Djava.util.logging.config.file="%CATALINA_BASE%\conf\logging.properties > " > -server -Xms1024m -Xmx1536m > > It seems to have improved, but the problem cropped up again. > > We use log4j to perform our logging and if you notice below, we have 2 > lines > of code logging some output one right after another. typically, there > is > just ms's in the log between these 2 log stmts, but when the slowdown > occurs, you can see there is about 2 secs delay which leads me to > believe > the appserver has exhausted its threads and the servlet cannot get a > thread > to execute on. We have disabled logging in the past to make sure the > logging itself wasn't the problem and we still encountered the > slowdown. > Note that the slowdown isn't just here in the log, but the entire > servlet > slows down, this part of the code is just a good indicator of how it is > affecting the servlet. > > These 2 log stmts follow one another and use log4j internally: > LOG("ICConnectorManager.doGet: Wait time to return response:" + > (System.currentTimeMillis() - waitStart) + "ms for request ID:" + > reqID); > LOG("ICConnectorManager.doGet: Looking up " + reqID + " and returning > response back to caller:" + sResponse); > > This is the output from those 2 log stmts, you can see the timestamp > shows 2 > seconds between. > 10/08/2009 09:06:24 DEBUG - ICConnectorManager.doGet: Wait time to > return > response:10125ms for request ID:14252-592 > 10/08/2009 09:06:26 DEBUG - ICConnectorManager.doGet: Looking up 14252- > 592 > and returning response back to caller: > > > My first question, what is the best tool to monitor this so we can get > an > accurate description of when the problems occur and what might be at > fault? > They just started running perfmon (on a Windows system), but as of yet > I > have not seen any data from it. Is there a better monitoring tool? > > Second question, what might we do to improve Tomcat performance? > Should we > continue to tweak the max threads and heap size? Any other Tomcat > settings > that we should look at that might directly relate to this server > slowdown? > > thank you > > > -- > View this message in context: http://www.nabble.com/Tracking-down-a- > Tomcat-slowdown-tp25081707p25081707.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
