| From: | Josh Berkus <josh(at)agliodbs(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pg(at)fastcrypt(dot)com |
| Cc: | Paul Tuckfield <paul(at)tuckfield(dot)com>, Anjan Dave <adave(at)vantage(dot)com>, Neil Conway <neilc(at)samurai(dot)com>, Dirk Lutzebäck <lutzeb(at)aeccom(dot)com>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Wierd context-switching issue on Xeon patch for 7.4.1 |
| Date: | 2004-04-22 02:53:24 |
| Message-ID: | 200404211953.24898.josh@agliodbs.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
Tom,
> As far as I can tell, this does reduce the rate of semop's
> significantly, but it does so by bringing the overall processing rate
> to a crawl :-(. I see 97% CPU idle time when using this patch.
> I believe what is happening is that the select() delay in s_lock.c is
> being hit frequently because the spin loop isn't allowed to run long
> enough to let the other processor get out of the spinlock.
Also, I tested it on production data, and it reduces the CSes by about 40%.
An improvement, but not a magic bullet.
--
Josh Berkus
Aglio Database Solutions
San Francisco
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Dave Cramer | 2004-04-22 03:06:41 | Re: Wierd context-switching issue on Xeon patch for 7.4.1 |
| Previous Message | Tom Lane | 2004-04-22 02:35:30 | Re: Wierd context-switching issue on Xeon patch for 7.4.1 |