All of this really stems on how your application interacts with Java/JVM. There is no really technotes from Macromedia or otherwise which will provide you with a best fit setting. Whatever else has been said ConcMarkSweep will give you worse performance than a Parallel GC - for sure. However f you are not sure, then simply remove any setting of the GC type and the JVM will take / use Parallel - if you have multiple CPU's you need to use them ;-)
What metrics have you ran before to give you memory consumption? (DO NOT rely on Task manager!) In Task manager ensure that you have the VM column visible, What you are probably seeing is timedout requests or queued requests being buffered into the system. Do you have a lot of Connection Reset by Peer's in the runtime logs? If you do, then CF is backlogging processing of the requests which will consume memory. I would certainly update your JVM as the GC in later versions is greatly improved. Thanks Neil -----Original Message----- From: Douglas Knudsen [mailto:[EMAIL PROTECTED] Sent: 01 March 2005 14:04 To: CF-Server Subject: Re: memory use and CF thanks for the reply Neil, very helpful. Info out there on this is scarce. I'm going to reply inline below. On Tue, 1 Mar 2005 10:03:52 -0000, Robertson-Ravo, Neil (RX) <[EMAIL PROTECTED]> wrote: > OK, > > Sorry I was delayed, damn timezones! OK, it looks as though you have a > fairly beefy machine...A few things you can do here (and these are never > documents by MM as they are no doubt out of scope of CF!) > > I would remove the -XX:+UseConcMarkSweepGC from your arguments and replace > it with -XX:+UseParallelGC. If you have a 4 processor box then you going to > suffer some performance problems with a ConcMarkSweep. This is interesting, Robi Sen's blog mentions the opposite and I think B Purcell's does too http://www.robisen.com/index.cfm?mode=entry&entry=FD4BE2FC-55DC-F2B1-FED0717 CC1C7E0AF we are using the 1.4.2 JVM shipping with CFMX. Interesting. > > Your Heap size looks scarily low - if its too low you will begin to get a > lot of GC's happening. For a 2GB box IO would set the heap to 1GB for Min > and Max. One thing to note is that there is no ideal setting for the heap - > it is entirely based on how much memory your application uses - and each > application is different. If you have not already I suggest you go and run > the Sun VisualGC application which is part of the JVMStat tool. > > http://java.sun.com/performance/jvmstat/ > I am working on getting this tool to work. I'm not a JAR head yet :) Hmm, I raised the heap to 1GB before and got the same issues. From the metrics monitoring, free heap space rarely goes below 400MB. Increasing the heap too big is also bad correct? Causing larger GCs? What I can't figure oiut is why windows task manager says the JRun instance is taking up more memory then it si though, see my first post in this thread. > Your symptoms all point to the fact that your app is a memory hogger - > probably due to largish queries (as MX uses around 4x more memory for a > query than CF5 does) or indeed just extensive use of compels procedures. > Yes, this is what I suspect too. One of the apps on this box is a heavy query laden piece of work that I have fought with teh developer on since inception. The developer sees no issue in a web page running 30 to 60 seconds if that's what the user wants. geesh. I'm segregating his app to a seperate instance soon. I expect some of these issues to go away then. In fact, I can sometimes see a large chunk, ~100MB, of free heap space get used at the same time this app has a long running request. Seconds later teh heap space is returned though, so it seems GC works. > I would redefined the following values (settings inline) -XX:MaxPermSize=64m > -XX:PermSize=48m -XX:NewSize=256m Ok, the MaxPermSize conflicts with this www.macromedia.com/support/coldfusion/ts/documents/java_lang_outofmemory.htm any reason to set it lower? What's your thoughts? Setting NewSize this high reduces GC frequency, correct? > > As for your XML settings - there a few things you can do. First off, what > is your Simultaneous connections set to? Within your proxy service the > activeHandlerThreads setting should be the same as your Simultaneous > connections value. And within your Scheduler service (this is sometimes > totally missing in CFMX) you should have > > <service class="jrunx.scheduler.SchedulerService" name="SchedulerService"> > <attribute name="bindToJNDI">true</attribute> > <attribute name="activeHandlerThreads">20</attribute> > <attribute name="maxHandlerThreads">1000</attribute> > <attribute name="minHandlerThreads">20</attribute> > <attribute name="threadWaitTimeout">60</attribute> > <attribute name="timeout">300</attribute> > </service> > This e-mail is from Reed Exhibitions (Oriel House, 26 The Quadrant, Richmond, Surrey, TW9 1DL, United Kingdom), a division of Reed Business, Registered in England, Number 678540. It contains information which is confidential and may also be privileged. It is for the exclusive use of the intended recipient(s). If you are not the intended recipient(s) please note that any form of distribution, copying or use of this communication or the information in it is strictly prohibited and may be unlawful. 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