Horton

Re: Wierd context-switching issue on Xeon

Dave Cramer <pg@fastcrypt.com>

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From: Dave Cramer <pg@fastcrypt.com>
To: Robert Creager <Robert_Creager@LogicalChaos.org>
Cc: Josh Berkus <josh@agliodbs.com>, Dirk_Lutzebäck <lutzeb@aeccom.com>, ohp@pyrenet.fr, Tom Lane <tgl@sss.pgh.pa.us>, Joe Conway <mail@joeconway.com>, "scott.marlowe" <scott.marlowe@ihs.com>, Bruce Momjian <pgman@candle.pha.pa.us>, pgsql-performance@postgresql.org, Neil Conway <neilc@samurai.com>
Date: 2004-05-02T15:39:22Z
Lists: pgsql-performance 
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