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Conference turris::digital_unix

Title:DIGITAL UNIX(FORMERLY KNOWN AS DEC OSF/1)
Notice:Welcome to the Digital UNIX Conference
Moderator:SMURF::DENHAM
Created:Thu Mar 16 1995
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:10068
Total number of notes:35879

9355.0. "How to disable CPU online?" by NETRIX::"[email protected]" (andy ) Wed Apr 02 1997 03:57

Hi, all

Does anyone know how to disable CPU in a running unix ?
I am testing the performance for my customer under 1 CPU & 2CPU,
the only way I know is to set cpu_enabled from Console, but my customer
told me in many other UNIX, it could be done by online unix command, so
I want to get the anwser!

AS4000 + DUNIX 4.0b

Thanks, 
Andy


[Posted by WWW Notes gateway]
T.RTitleUserPersonal
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9355.1Try man psradmHERON::BLOMBERGTrapped inside the universeWed Apr 02 1997 04:411
    
9355.2Use the console. PERFOM::HENNINGWed Apr 02 1997 08:2317
    no DON'T use psradm
    
    use the console
    
    see 3827.2 in this conference
    see also mvblab::sable note 1835 and its reply .1
    
    And in the manpage for psradm, note the following:
    
    RESTRICTION
    
    Do not use the psradm command to disable CPUs when benchmarking perfor-
    mance, because the command does not provide an accurate reflection of the
    performance of a system that actually has fewer CPUs.  Accurate performance
    results are obtained only when you disable the CPUs at the SRM console com-
    mand level.
    
9355.32->1 cpu with psradm doesn't equal 1 cpuSMURF::WOODWARDThu Apr 03 1997 08:519
    To get "true" single processor performance, you just can't use psradm
    to shutdown a cpu.  Using the psradm command will not turn off SMP
    locking when going down to 1 processor.  Thus you will be paying the
    SMP price on a system running only one processor.  You need to shutdown
    the system to the console, disable the proper processors, then reboot
    the system.  
    
    /jim
    
9355.4UTRUST::PILMEYERQuestions raise the doubtThu Apr 03 1997 08:584
    In addition to what John said in .2, the psradm command doesn't work in
    V4.0B anyway (QAR 51839).
    
    -Han