| From: | Dave Cramer <pg(at)fastcrypt(dot)com> |
|---|---|
| To: | Josh Berkus <josh(at)agliodbs(dot)com> |
| Cc: | Anjan Dave <adave(at)vantage(dot)com>, Dirk Lutzebäck <lutzeb(at)aeccom(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-performance(at)postgreSQL(dot)org, Neil Conway <neilc(at)samurai(dot)com> |
| Subject: | Re: Wierd context-switching issue on Xeon |
| Date: | 2004-04-21 02:41:03 |
| Message-ID: | 1082515263.1558.214.camel@localhost.localdomain |
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| Thread: | |
| Lists: | 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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