Re: Weird context-switching performance

From: Milo Hyson (milo_at_cyberlifelabs.com)
Date: 02/01/04

  • Next message: Milo Hyson: "Re: Weird context-switching performance [RESOLVED]" 
    To: Julian Elischer <julian@elischer.org>
Date: Sat, 31 Jan 2004 18:00:39 -0800

    We don't have any other systems that are as similar as the two in the
    test, however we did plot context-switching performance against CPU and
    memory performance on several systems to see if anything jumped out. We
    found that beastie (the 2200+) is doing only about 26% of the
    task-switches/dhrystone that the other systems were, which were all
    pretty much about equal with each other. This is consistent with the
    observation that appserver (the 2100+) is four-times as fast. I think we
    can probably conclude that beastie is running slower than it should.

    So the question still remains. What could affect context-switching to
    this degree yet not show up in other benchmarks? 

    -- 
Milo Hyson
Chief "Mad" Scientist
CyberLife Labs, LLC
On Sat, 2004-01-31 at 15:35, Julian Elischer wrote:
> On Sat, 31 Jan 2004, Milo Hyson wrote:
> 
> > We've got these two very similar machines that are exhibiting
> > drastically different context-switching performance. The slower of the
> > two is actually task-switching at four times the rate of the other.
> > We've gone through several benchmarks and are at a complete loss to
> > explain it. We've set up a page documenting our efforts:
> > 
> > http://www.cyberlifelabs.com/cs-benchmark/
> > 
> > I would appreciate it if someone could offer some insight into what
> > affects context-switching. Is there some obscure kernel variable that
> > we've overlooked? Or is it just one of those unexplainable feng-shui
> > situations?
> > 
> 
> Which is the abnormal machine?
> i.e. is machine 1 faster than all other similar machines or is machine B
> slower?
> 
> 
> 
> > Thanks in advance.
> > 
> > -- 
> > Milo Hyson
> > Chief "Mad" Scientist
> > CyberLife Labs, LLC
> > 
> > _______________________________________________
> > freebsd-hackers@freebsd.org mailing list
> > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
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> > 
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  • Next message: Milo Hyson: "Re: Weird context-switching performance [RESOLVED]"

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    • Re: Weird context-switching performance
      ... On Sat, 31 Jan 2004, Milo Hyson wrote: ... > drastically different context-switching performance. ... The slower of the ... > two is actually task-switching at four times the rate of the other. ...
      (freebsd-hackers)
    • Weird context-switching performance
      ... We've got these two very similar machines that are exhibiting ... drastically different context-switching performance. ... The slower of the ... two is actually task-switching at four times the rate of the other. ...
      (freebsd-hackers)