The ability of Tomcat (or any other Java application) to use multiple CPUs depends on if the JVM can support multiple CPUs. Sun's JVM for Windows uses native threads which the OS can schedule across multiple CPUs. Clearly, your test application shows this. I believe Java threads are mapped one-to-one to native Windows threads. With concurrent Java threads, the OS is basically determining which processors handle which threads. If you want to see what's happening in Tomcat when this is going on, try a profiler like JProfiler. You can also press Ctrl-break in the console window to get a thread dump of the JVM. If there's any kind of blocking going on, this should help identify that.
>>> [EMAIL PROTECTED] 12/2/2004 9:40:36 PM >>> Hi, I have a setup of 10 application servers using Tomcat 4/5, jsdk 1.4.2_02, SMP, win2k. In watching the performance under load I am concerned that only one CPU is being utilized at a time. To validate my theory I try hitting the application server with a request to generate a large report and then making another connection. The second connection is painfully slow and task manager only reports a 50% CPU utilization. After doing some reading on SMP/native threads and windows, I wrote a test java application that spawns n infinite loop threads from a single JVM with a delay between each creation. Sure enough one cpu (task manager reporting 50%) and then the other cpu are consumed (task manager reporting 100%). This test tells me that Java is capable of using both CPU's via native threading and some black magic in the windows dll's but that this scenario isn't happening in tomcat. Is it possible for tomcat to use more than one CPU or is there a critical flaw in my logic? -Dan --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
