Re: Wierd context-switching issue on Xeon - Mailing list pgsql-performance

From Bruce Momjian
Subject Re: Wierd context-switching issue on Xeon
Date
Msg-id 200405200120.i4K1KKm06350@candle.pha.pa.us
Whole thread Raw
In response to Re: Wierd context-switching issue on Xeon  (Dave Cramer <pg@fastcrypt.com>)
Responses Re: Wierd context-switching issue on Xeon  (Robert Creager <Robert_Creager@LogicalChaos.org>)
Re: Wierd context-switching issue on Xeon  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
Did we ever come to a conclusion about excessive SMP context switching
under load?

---------------------------------------------------------------------------

Dave Cramer wrote:
> Robert,
>
> The real question is does it help under real life circumstances ?
>
> Did you do the tests with Tom's sql code that is designed to create high
> context switchs ?
>
> Dave
> On Sun, 2004-05-02 at 11:20, Robert Creager wrote:
> > Found some co-workers at work yesterday to load up my library...
> >
> > The sample period is 5 minutes long (vs 2 minutes previously):
> >
> > Context switches -          avg    max
> >
> > Default 7.4.1 code :       48784 107354
> > Default patch - 10 :       20400  28160
> > patch at 100       :       38574  85372
> > patch at 1000      :       41188 106569
> >
> > The reading at 1000 was not produced under the same circumstances as the prior
> > readings as I had to replace my device under test with a simulated one.  The
> > real one died.
> >
> > The previous run with smaller database and 120 second averages:
> >
> > Context switches -          avg    max
> >
> > Default 7.4.1 code :       10665  69470
> > Default patch - 10 :       17297  21929
> > patch at 100       :       26825  87073
> > patch at 1000      :       37580 110849
> --
> Dave Cramer
> 519 939 0336
> ICQ # 14675561
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 7: don't forget to increase your free space map settings
>

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