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  • 1.  Dual-core Server Processor Utilization

    Posted Tue February 09, 2010 11:39 PM

    Originally posted by: alvinsim


    We have a p550 server running AIX 5.3 and it has Two Dual-Core Processors. For system monitoring, we have nmon turned on and capturing data every 15 minutes.

    When the server is experiencing heavy load, we've noticed that for every processor, the first core is always very much higher than the second core or vice-versa. For example in the nmon report, CPU1 is utilized at around 60 - 70% but CPU2 is at around 20%. CPU3 is is utilized at 50 - 60% and CPU4 is around 30%.

    Is this normal? I've noticed this pattern in most of the multi-core servers we have.


  • 2.  Re: Dual-core Server Processor Utilization

    Posted Wed February 10, 2010 06:54 AM

    Originally posted by: hdkutz


    Hello,
    you may have SMT active?
    Execute
    1. smtctl
    on your machine.
    Also execute
    1. lsconf
    and look for "Number of Processors".

    Cheers,
    ku


  • 3.  Re: Dual-core Server Processor Utilization

    Posted Wed February 10, 2010 10:18 AM

    Originally posted by: MarkTaylor


    SMT is enabled by default, so for every online virtual processor you will get 2 x logical processors .. the first one is the physical, then second one is the SMT part .. SMT can in some circumstances and workloads give you 40% extra from a single processor .. however, not always and not for all workloads hence the numbers you are seeing ..

    See this thread ..

    http://www.ibm.com/developerworks/forums/thread.jspa?threadID=317788&tstart=0

    HTH
    Mark Taylor


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