start with monitoring. Find out which action/servlet/whatever is taking time. Go further down and check where the time is spent (a service object or something). Narrow it down, than solve it :-)
regards Leon
On 6/1/07, Stéphane Hanser <[EMAIL PROTECTED]> wrote: > You are right about synchronized blocks. I removed every synchronized > instruction for tests purposes and it "unleashed the cpu" ;) > > It may be a problem with memory too. By disabling the cache of iBatis I > noticed an overloading of the CPU, which is understandable considering the > circumstance. > > However, removing some synchronized blocks will cause concurrent access > issues when a user "mass clicks". Is it possible to configure tomcat to > queue one's requests instead of executing the in parallel ? > > Thanks, > > Stéphane H. > > PS: thanks for the jmeter tip ;) > > > -----Message d'origine----- > De: David Delbecq [mailto:[EMAIL PROTECTED] > Envoyé: vendredi 1 juin 2007 10:59 > À: Tomcat Users List > Objet: Re: WebApp really slow, Where do I start looking? > > Considering CPU usage, it is not > 1) a java memory problem, if java memory was full, garbage collector > would start using lots of cpu > 2) a time consuming java code. > > It might be one of following > 1) synchronized blocks in your code, that would prevent 2 simultaneoous > users from doing some operations. > 2) use of SingleThreadModel, which has same effect as above > 3) Network congestion, you server simply can't send the response to > client due to a too small network pipe (80 requests / second resulting > each in an about 20k response need a bandwidth of more than 12Mbits) > 4) A too small physical memory on system. Eg you configure tomcat to use > 1G memory but your server has only 512M available, resulting in memory > pagination (swap) and sleeping of java process during pagination process > (typically, on unix server, you will see a high % of CPU dedicated to > system instead of idle when this happen) > > > One way to test your server performance during heavy is to use apache > jmeter. > > > En l'instant précis du 01/06/07 10:48, Stéphane Hanser s'exprimait en > ces termes: > > Hello, > > > > I've been working on my project for months now, it is my first WebApp > > project. Yesterday, I deployed the project on my dedicated server and > > a soon as I reached about 80 users, the webapp became really slow. > > However, the cpu usage of the server was very low (never more than > > 15-20%). I have no idea of what is the cause of this slowness (server > > config, bad programming..). > > > > Can someone help me to diagnostic the problem? Where shoul I start > > looking? > > > > thanks in advance, > > > > Stéphane H. > > > > > > > > > > > > --------------------------------------------------------------------- > > To start a new topic, e-mail: users@tomcat.apache.org > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > --------------------------------------------------------------------- > To start a new topic, e-mail: users@tomcat.apache.org > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > --------------------------------------------------------------------- > To start a new topic, e-mail: users@tomcat.apache.org > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > --------------------------------------------------------------------- To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
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