André Warnier wrote: > Hi again. > > Now that I have (with your help) established some basic facts, I have a > practical case for analysis. > > Before I get into details (because this is quite long), I'd like to > explain the reason why I'm asking this. > We have been testing a Tomcat application from a vendor. It works very > nicely when it is started on a test system, and does what we expect. > But the load it imposes on our test Tomcat at startup, makes me a bit > insecure about deploying it to a production server, before I really > understand what is happening. > Not being a Java or Tomcat expert, I'm just trying to collect some > pointers, to see if I can do something about what I am observing, or if > that's it and we just have to live with it. > The main thing is, I don't even know where to start, so I would > appreciate some help, even if very basic. > There is quite a bit of data below. > > We have an old clunker PC (Pentium II, 512 Mb Ram, average ATA disks), > which we use to test some applications (not only Java/Tomcat). > Its a Linux system, and runs this Tomcat : > Using CATALINA_BASE: /usr/share/tomcat5.5 > Using CATALINA_HOME: /usr/share/tomcat5.5 > Using CATALINA_TMPDIR: /usr/share/tomcat5.5/temp > Using JRE_HOME: /usr/lib/jvm/java-1.5.0-sun > Server version: Apache Tomcat/5.5 > Server built: Jan 20 2008 12:32:00 > Server number: 5.5.20.0 > OS Name: Linux > OS Version: 2.6.18-6-686 > Architecture: i386 > JVM Version: 1.5.0_14-b03 > JVM Vendor: Sun Microsystems Inc. > > The full command used to start Tomcat is : > /usr/lib/jvm/java-1.5.0-sun/bin/java > -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager > -Djava.util.logging.config.file=/var/lib/tomcat5.5/conf/logging.properties > -Djava.awt.headless=true -Xmx256M -server > -Djava.endorsed.dirs=/usr/share/tomcat5.5/common/endorsed -classpath > :/usr/lib/jvm/java-1.5.0-sun/jre//lib/jcert.jar:/usr/lib/jvm/java-1.5.0-sun/jre//lib/jnet.jar:/usr/lib/jvm/java-1.5.0-sun/jre//lib/jsse.jar:/usr/share/tomcat5.5/bin/bootstrap.jar:/usr/share/tomcat5.5/bin/commons-logging-api.jar > > -Djava.security.manager > -Djava.security.policy==/var/lib/tomcat5.5/conf/catalina.policy > -Dcatalina.base=/var/lib/tomcat5.5 -Dcatalina.home=/usr/share/tomcat5.5 > -Djava.io.tmpdir=/var/lib/tomcat5.5/temp > org.apache.catalina.startup.Bootstrap start > > Under Tomcat there, there is an application which we get from outside > and of which we do not have the source. This application is loaded at > Tomcat startup. > > When Tomcat has been running for a while, but the system and Tomcat are > basically idle, a "top" with the option "n" (sort by memory usage), > shows this (first few lines only) : > > top - 10:15:54 up 162 days, 16:25, 2 users, load average: 0.19, 0.09, > 0.03 > Tasks: 82 total, 1 running, 81 sleeping, 0 stopped, 0 zombie > Cpu(s): 2.0%us, 0.3%sy, 0.0%ni, 97.7%id, 0.0%wa, 0.0%hi, 0.0%si, > 0.0%st > Mem: 516920k total, 509716k used, 7204k free, 71992k buffers > Swap: 1297564k total, 131340k used, 1166224k free, 95148k cached > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 6226 tomcat55 25 0 506m 191m 10m S 0.0 37.9 140:26.15 java > 5937 root 22 0 267m 26m 8056 S 0.0 5.2 25:26.88 java > 24608 root 23 0 260m 15m 9332 S 0.0 3.1 0:02.08 java > 24638 root 15 0 29564 15m 5984 S 0.0 3.0 0:02.16 apache2 > 24627 efs 15 0 16964 12m 1968 S 0.0 2.6 0:06.68 MiraLoader.pl > 24662 www-data 15 0 29564 10m 1632 S 0.0 2.2 0:02.91 apache2 > 24668 www-data 16 0 29564 10m 1624 S 0.0 2.2 0:02.50 apache2 > 24663 www-data 15 0 29564 10m 1620 S 0.0 2.2 0:02.78 apache2 > etc.. > (the other 2 java processes are separate java daemons, nothing to do > with Tomcat). > > At this point Tomcat and this external application are very responsive, > at least in single-user mode. We have not really done yet a multi-user > test. > > Now, if I stop and restart Tomcat, for something like 6 minutes after > that, the same top display shows this kind of thing : > (There are 4 consecutive snapshots here, taken at more or less regular > intervals during the 6 minutes) > > I) > top - 12:44:56 up 162 days, 18:54, 3 users, load average: 0.99, 0.27, > 0.08 > Tasks: 85 total, 3 running, 82 sleeping, 0 stopped, 0 zombie > Cpu(s): 98.0%us, 2.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, > 0.0%st > Mem: 516920k total, 351160k used, 165760k free, 54548k buffers > Swap: 1297564k total, 70000k used, 1227564k free, 128152k cached > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 2864 tomcat55 25 0 463m 40m 11m R 97.9 7.9 0:25.62 java > 5937 root 16 0 267m 24m 8056 S 0.0 4.9 25:38.84 java > 24608 root 23 0 260m 15m 9332 S 0.0 3.1 0:02.17 java > 24638 root 15 0 29564 15m 5984 S 0.0 3.0 0:02.16 apache2 > 24627 efs 15 0 16964 12m 1968 S 0.0 2.6 0:06.74 MiraLoader.pl > 24664 www-data 15 0 29692 12m 3428 S 0.0 2.5 0:04.46 apache2 > etc... > > II) > top - 12:48:07 up 162 days, 18:57, 3 users, load average: 1.70, 0.96, > 0.38 > Tasks: 85 total, 2 running, 83 sleeping, 0 stopped, 0 zombie > Cpu(s): 95.0%us, 5.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, > 0.0%st > Mem: 516920k total, 483396k used, 33524k free, 55680k buffers > Swap: 1297564k total, 70000k used, 1227564k free, 138644k cached > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 2864 tomcat55 25 0 461m 159m 12m R 99.2 31.5 3:30.88 java > 5937 root 16 0 267m 24m 8056 S 0.0 4.9 25:38.84 java > 24608 root 23 0 260m 15m 9332 S 0.0 3.1 0:02.17 java > 24638 root 15 0 29564 15m 5984 S 0.0 3.0 0:02.16 apache2 > 24627 efs 15 0 16964 12m 1968 S 0.0 2.6 0:06.74 MiraLoader.pl > 24664 www-data 15 0 29692 12m 3428 S 0.0 2.5 0:04.46 apache2 > etc... > > III) > top - 12:50:20 up 162 days, 19:00, 3 users, load average: 1.54, 1.15, > 0.53 > Tasks: 85 total, 2 running, 83 sleeping, 0 stopped, 0 zombie > Cpu(s): 94.4%us, 5.3%sy, 0.0%ni, 0.0%id, 0.3%wa, 0.0%hi, 0.0%si, > 0.0%st > Mem: 516920k total, 509016k used, 7904k free, 51668k buffers > Swap: 1297564k total, 70000k used, 1227564k free, 142828k cached > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 2864 tomcat55 25 0 461m 184m 12m R 98.5 36.6 5:40.81 java > 5937 root 16 0 267m 24m 8056 S 0.0 4.9 25:38.84 java > 24608 root 23 0 260m 15m 9332 S 0.0 3.1 0:02.17 java > 24638 root 15 0 29564 15m 5984 S 0.0 3.0 0:02.16 apache2 > 24627 efs 15 0 16964 12m 1968 S 0.0 2.6 0:06.74 MiraLoader.pl > 24664 www-data 15 0 29692 12m 3428 S 0.0 2.5 0:04.46 apache2 > etc... > > IV) (Now it's back to idle, and Tomcat is responding) > > top - 12:51:48 up 162 days, 19:01, 3 users, load average: 1.28, 1.19, > 0.60 > Tasks: 85 total, 1 running, 84 sleeping, 0 stopped, 0 zombie > Cpu(s): 2.0%us, 0.3%sy, 0.0%ni, 97.7%id, 0.0%wa, 0.0%hi, 0.0%si, > 0.0%st > Mem: 516920k total, 490692k used, 26228k free, 43552k buffers > Swap: 1297564k total, 70000k used, 1227564k free, 130936k cached > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 2864 tomcat55 25 0 482m 188m 12m S 0.0 37.4 6:46.74 java > 5937 root 16 0 267m 24m 8056 S 0.0 4.9 25:38.86 java > 24608 root 23 0 260m 15m 9332 S 0.0 3.1 0:02.17 java > 24638 root 15 0 29564 15m 5984 S 0.0 3.0 0:02.16 apache2 > 24627 efs 15 0 16964 12m 1968 S 0.0 2.6 0:06.75 MiraLoader.pl > 24664 www-data 15 0 29692 12m 3428 S 0.0 2.5 0:04.46 apache2 > etc... > > In other words, while this application is being loaded, our Tomcat and > the whole system are totally unresponsive for about 5 minutes. > I know that it has to do with this application, for a number of reasons, > two of them being : > - if I do not start the application at Tomcat startup, Tomcat is > responsive after 15 seconds, instead of 5 minutes > - the Tomcat logfile shows me where things are not moving anymore during > those 5 minutes, and that is at the point of some message from this > application > - if I stop and restart this application separately with the Tomcat > Manager, I get the same 5 minute-freeze as when starting Tomcat > - I know also that this application has to read and parse a 25 Mb file > of XML data containing some data structure that it needs later on. I > don't know how it parses this, just that it does. > > Now my questions are of the kind : > Our production servers are ASP servers, where several customers would be > using this same application, each customer with its own 25 Mb XML file > of data. They are more powerful servers, but if I have 5 customers and > these things compete with one another for memory or resources, I could > have a server that is unresponsive for a hour maybe at start. > > So basically, I am asking if there are any parameters I can vary for the > application startup or Tomcat in general, to evaluate the behaviour > under different circumstances, or if I should put more RAM in the > server, or if I should lower or raise the amount of memory available to > Tomcat (and how), etc.. > I am also a bit surprised about the amounts I see in terms of memory > usage, but not being an expert, I have not really anything to compare > them with. It's just that these java applications seem very hungry in > memory, if what is shown is really what they are using. For comparison, > we have other applications running on that server, of comparable > complexity, and they use 10-15 Mb apiece. > > Anybody feel like commenting ?
If the production servers are all much faster, then your observation that an ancient PC is slow starting up Tomcat is probably moot, no? Try to test the install on a comparable bit of hardware. Having said that, parsing XML can be a memory intensive operation as well, so your old box could be experiencing problems there - check the garbage collection log. p > --------------------------------------------------------------------- > 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]
