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

From Dave Cramer
Subject Re: Wierd context-switching issue on Xeon
Date
Msg-id 1082515263.1558.214.camel@localhost.localdomain
Whole thread Raw
In response to Re: Wierd context-switching issue on Xeon  (Josh Berkus <josh@agliodbs.com>)
Responses Re: Wierd context-switching issue on Xeon
List pgsql-performance
I modified the code in s_lock.c to remove the spins

#define SPINS_PER_DELAY         1

and it doesn't exhibit the behaviour

This effectively changes the code to


while(TAS(lock))
    select(10000); // 10ms

Can anyone explain why executing TAS 100 times would increase context
switches ?

Dave


On Tue, 2004-04-20 at 12:59, Josh Berkus wrote:
> Anjan,
>
> > Quad 2.0GHz XEON with highest load we have seen on the applications, DB
> > performing great -
>
> Can you run Tom's test?   It takes a particular pattern of data access to
> reproduce the issue.
--
Dave Cramer
519 939 0336
ICQ # 14675561


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