Dave, You made an excellent point regarding "thread thrashing". Although I don't know if "thread thrashing" is completely responsible for the behavior that Ben is experiencing, it can certainly contribute. If my memory serves me correctly, the NT and 2000 threading scheduler is based on a "preemptive" model, vs a Unix operating system's threading scheduler is based on a "time-slicing" model. The difference being that a time slicing scheduler will eventually give CPU time to lower priority threads, whereas a preemptive scheduler may not. It one of many reasons to consider using a Unix server if you expect to experience heavy traffic/load on your site.
You can write a simple program to execute a "group" threads and then one by one, launch another thread within your "group" and watch your performance. If your performance suddenly deteriorates around 50 or 100 threads, than you may need to upgrade your machine to include more CPU's. Or, if you are really anticipating a heavy load/traffic on your server, consider porting to a Unix server. That's one of the advantages of using JSP's and Java, you can easily port from one platform to the other if necessary. Celeste -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Wednesday, October 03, 2001 6:09 PM To: JRun-Talk Subject: RE: Re: JRun does not responds after 100 threads Guys, How many processors do you have running on your system? I do not believe that this is a JRUN or java issue but a "tread thrashing" issue. Basically only one thread can run at any exact moment upon a CPU. By running 100 threads at once, the machine is spending a lot of resources upon just switching between threads than running them. Another issue to consider is that NT's thread model is not the best going. I just got a dual Pentium set up and it provides a little boost, but not what I had hoped for:( As for our PRD systems, we use some of the larger SUN systems and they handle threading very well. After some experience we have found out that setting more than about 20 threads to a process(not jrun in particular) provides little benefit due to I/O & other things. This machine though has 64 processors to utilize. Makarand, It sounds as if you might be upgrading your hardware to a UNIX system to handle your load. A big perk with JSP's is that your code won't have to change one bit:) Dave -----Original Message----- From: bgroeneveld Sent: Wednesday, October 03, 2001 6:08 PM To: jrun-talk Cc: bgroeneveld Subject: Re: JRun does not responds after 100 threads Makarand, I have seen similar behavior. I think there may be a JRun problem. If I setup a threadpool of 50 with an idle thread timeout of 60, then after a fresh jrun startup and no activity NT perfmon shows the threadpool gets cleaned up. Or if I send a burst of 100 persistent connections, then after 60s the threadcount goes from 150 to 100. I am going to try an experiment with the IBM jvm later this week to make sure this isn't VM related. I've had best performance leaving the threadpool at 1, even thought that's not what's desired, my server/VM lives much longer that way. I'm assuming that changing the threadpool causes a fault inside JRun. Anyone know more? BenG. JOGALEKAR,MAKARAND (HP-Boise,ex1) wrote: >Hello, > >We are having lot of problems with JRun 3.0 or Jrun3.1, >If we get high volume and the thread count goes beyond 100, it does not >respond. > >We are just using servlets with Netscape Exterprise server 3.6 with EJB's at >all. > >We have disabled the EJB option for performance and also tried different >options >by setting initial thread count to 50 with maximum thread count to 500..but >nothing works.. > >Any help ?? > >Thanks, >-Makarand > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Get the mailserver that powers this list at http://www.coolfusion.com Archives: http://www.mail-archive.com/[email protected]/ Unsubscribe: http://www.houseoffusion.com/index.cfm?sidebar=lists
