Re: Dual Xeon + HW RAID question

From: Jord Tanner <jord(at)indygecko(dot)com>
To: "SZUCS =?ISO-8859-1?Q?G=E1bor?=" <surrano(at)mailbox(dot)hu>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Dual Xeon + HW RAID question
Date: 2003-07-22 17:35:52
Message-ID: 1058895352.4339.32.camel@gecko
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The Linux 2.6 kernel will have the ability to set CPU affinity for
specific processes. There is a patch for the 2.4 kernel at
http://www.kernel.org/pub/linux/kernel/people/rml/cpu-affinity

RedHat 9 already has support for CPU affinity build in.

The July 2003 issue of Linux Journal includes a little C program (on
page 20) that gives you a shell level interface to the CPU affinity
system calls, so you can dynamically assign processes to specific CPUs.
I haven't tried it, but it looks very cool (my only SMP machine is in
production, and I don't want to mess with it). If you try it out, please
share your experiences with the list.

Jord Tanner
Independent Gecko Consultants

On Tue, 2003-07-22 at 10:10, SZUCS Gábor wrote:
> "by default" -- do you mean there is a way to tell Linux to favor the second
> real cpu over the HT one? how?
>
> G.
> ------------------------------- cut here -------------------------------
> ----- Original Message -----
> From: "Bruce Momjian" <pgman(at)candle(dot)pha(dot)pa(dot)us>
> Sent: Tuesday, July 22, 2003 6:26 PM
> Subject: Re: [PERFORM] Dual Xeon + HW RAID question
>
>
> > Right, I simplified it. The big deal is whether the OS favors the
> > second real CPU over one of the virtual CPU's on the same die --- by
> > default, it doesn't. Ever if it did work perfectly, you are talking
> > about going from 1 to 1.4 or 2 to 2.8, which doesn't seem like much.
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 8: explain analyze is your friend
--
Jord Tanner <jord(at)indygecko(dot)com>

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