Horton

Re: Wierd context-switching issue on Xeon

Jeff <threshar@torgo.978.org>

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From: Jeff <threshar@torgo.978.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Bruce Momjian <pgman@candle.pha.pa.us>, Joe Conway <mail@joeconway.com>, Neil Conway <neilc@samurai.com>, josh@agliodbs.com, lutzeb@aeccom.com, pgsql-performance@postgresql.org, "scott.marlowe" <scott.marlowe@ihs.com>
Date: 2004-04-20T12:46:12Z
Lists: pgsql-performance 
On Apr 19, 2004, at 8:01 PM, Tom Lane wrote:
[test case]

Quad P3-700Mhz, ServerWorks, pg 7.4.2 - 1 process: 10-30 cs / second
                  							   2 process: 100k cs / sec
								   3 process: 140k cs / sec
								   8 process: 115k cs / sec

Dual P2-450Mhz, non-serverworks (piix)  - 1 process 15-20 / sec
             						            2 process 30k / sec
           							  3 (up to 7) process: 15k /sec

(Yes, I verified with more processes the cs's drop)

And finally,

6 cpu sun e4500, solaris 2.6, pg 7.4.2: 1 - 10 processes: hovered 
between 2-3k cs/second (there was other stuff running on the machine as 
well)


Verrry interesting.
I've got a dual G4 at home, but for convenience Apple doesn't ship a 
vmstat that tells context switches

--
Jeff Trout <jeff@jefftrout.com>
http://www.jefftrout.com/
http://www.stuarthamm.net/