Weblogic CPU usage on Multi CPU Solaris box - Weblogic

This is a discussion on Weblogic CPU usage on Multi CPU Solaris box - Weblogic ; Environment : Solaris box with 6 cpus Weblogic Admin Server 7.0 sp2 Weblogic Managed Server 7.0 sp2 1.3.1_06 JVM License file for 1 CPU I guess I am just after some clarification of weblogic cpu allocation/behaviour with the above licensing ...

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Thread: Weblogic CPU usage on Multi CPU Solaris box

  1. Weblogic CPU usage on Multi CPU Solaris box

    Environment :

    Solaris box with 6 cpus
    Weblogic Admin Server 7.0 sp2
    Weblogic Managed Server 7.0 sp2
    1.3.1_06 JVM
    License file for 1 CPU

    I guess I am just after some clarification of weblogic cpu allocation/behaviour with the above licensing constraint.

    When we do a prstat, we see that the weblogic processes switch between the 6 different CPUs on the box,as opposed to being pegged to a single CPU. However, it does seem that only 1 CPU is being utilized at any one time, which would fit the licensing constraint.

    Can someone confirm that this is the correct behaviour ?

    Any comments much appreciated.

  2. Re: Weblogic CPU usage on Multi CPU Solaris box

    I don't think the license will restrict the JVM from using multiple CPU's on
    a multi-processor box. However, if you have a 1 CPU license, and you are
    using WLS on a 6 CPU machine, the legality of what you are doing may be
    questioned. But, I'm not an attorney.

    Bill


    "damien dallimore" wrote in message
    news:27173215.1105576135077.JavaMail.root@jserv5.. .
    > Environment :
    >
    > Solaris box with 6 cpus
    > Weblogic Admin Server 7.0 sp2
    > Weblogic Managed Server 7.0 sp2
    > 1.3.1_06 JVM
    > License file for 1 CPU
    >
    > I guess I am just after some clarification of weblogic cpu

    allocation/behaviour with the above licensing constraint.
    >
    > When we do a prstat, we see that the weblogic processes switch between the

    6 different CPUs on the box,as opposed to being pegged to a single CPU.
    However, it does seem that only 1 CPU is being utilized at any one time,
    which would fit the licensing constraint.
    >
    > Can someone confirm that this is the correct behaviour ?
    >
    > Any comments much appreciated.




  3. Re: Weblogic CPU usage on Multi CPU Solaris box

    Thanks for taking the time to reply, but I am really after a more scientific clarification of how weblogic behaves on a multi cpu machine with a single cpu license ie: is execution pegged to 1 single CPU, or is execution switched over the different CPUs whilst still only utilizing 1 of those cpus at any given time.

    We do have a multi cpu license, but would also like to have clarification of the aforementioned situation.

    Cheers.

  4. Re: Weblogic CPU usage on Multi CPU Solaris box

    You can bind a process to a processor with a "pbind" command on
    solaris. Unless you do the pbind OS can run your process on any
    processor available.

    You can findout if the prcess is switching processors with "top"
    command. If you don't have top then you can findout by " ps -p pid -o
    pid,psr"


  5. Re: Weblogic CPU usage on Multi CPU Solaris box

    Academically, I don't think that it is a WebLogic issue. It is a JVM and OS
    issue. I think the 1.3.1 JVM and earlier versions do not take advantage of
    multiprocessor machines. 1.4 and later, apparently, do take advantage of it
    to a greater extent by allowing garbage collection to proceed in a separate
    thread on another cpu.

    We saw this issue on our dual processor clients that were running 1.3.1. The
    extra processor was added to enhance performance, but we got no measurable
    gain in performance. I don't know what the results are of the benchmarks
    with the 1.4.1 clients. My first paragraph is basically parroting what our
    SA's said about the 1.3.1 jvm and the changes made in 1.4 and these links
    seem to support that:

    http://java.sun.com/docs/hotspot/gc5.0/gc_tuning_5.html
    http://developers.sun.com/techtopics...gecollection2/

    However, it is curious that there is not any mention of application tasks
    proceeding in parallel, in separate threads, on separate processors.

    Bill

    "damien dallimore" wrote in message
    news:25626353.1105651063236.JavaMail.root@jserv5.. .
    > Thanks for taking the time to reply, but I am really after a more

    scientific clarification of how weblogic behaves on a multi cpu machine with
    a single cpu license ie: is execution pegged to 1 single CPU, or is
    execution switched over the different CPUs whilst still only utilizing 1 of
    those cpus at any given time.
    >
    > We do have a multi cpu license, but would also like to have clarification

    of the aforementioned situation.
    >
    > Cheers.




  6. Re: Weblogic CPU usage on Multi CPU Solaris box

    Damien,

    "damien dallimore" wrote in message news:25626353.1105651063236.JavaMail.root@jserv5.. .
    > Thanks for taking the time to reply, but I am really after a more scientific clarification of how weblogic behaves on a multi cpu

    machine with a single cpu license ie: is execution pegged to 1 single CPU, or is execution switched over the different CPUs whilst
    still only utilizing 1 of those cpus at any given time.
    >
    > We do have a multi cpu license, but would also like to have clarification of the aforementioned situation.


    First, it's not WebLogic issue. Java applications have no ability to control
    their execution at this level.

    As for the only one processor being loaded - it's likely Solaris issue if at
    all. Under lesser load it is not really important which CPU is doing work
    (unless the CPUs at different pay rates

    BTW, how do you identify that it is "only utilizing 1 of those cpus
    at any given time"?

    σΜΑΧΑ



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