More to ponder...I repeated this run on my laptop now booted in redhat 6.2. I change the JRun web server min threads from 1 to 50, and change the idle thread timeout from 300 to 60s. Now I fire up the JRun 3.1 default server. I check gtop, and I see jrun having 95 processes (a linux thread is practically a process). 60 seconds later this number drops to 46. Hmm. That doesn't seem right. It should be threads beyond the pool of 50 that get killed. Ok, so now I set the min threads back to 1, restart, and JRun default has 44 threads. Now all these threads are idle, none are vying for CPU. I have a hard time accepting this as thread-thrashing or NT vs unix. These are the exact same results I see on NT for JRun 3.0 sp2. I think the thread pool's not working, or I don't understand these parameters. What am I missing? Thanks, BenG.
Haseltine, Celeste wrote: >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
