From: Joe Korty <joe.korty@ccur.com>
To: Arjan van de Ven <arjanv@redhat.com>
Cc: Ethan Weinstein <lists@stinkfoot.org>,
linux-kernel@vger.kernel.org,
William Lee Irwin III <wli@holomorphy.com>
Subject: Re: 2.6.1 and irq balancing
Date: Sun, 11 Jan 2004 11:50:12 -0500 [thread overview]
Message-ID: <20040111165012.GA24746@tsunami.ccur.com> (raw)
In-Reply-To: <1073814681.4431.5.camel@laptop.fenrus.com>
On Sun, Jan 11, 2004 at 10:51:22AM +0100, Arjan van de Ven wrote:
> On Sun, 2004-01-11 at 00:14, Ethan Weinstein wrote:
> > Greetings all,
> >
> > I upgraded my server to 2.6.1, and I'm finding I'm saddled with only
> > interrupting on CPU0 again. 2.6.0 does this as well. This is the
> > Supermicro X5DPL-iGM-O (E7501 chipset), 2 Xeons@2.4ghz HT enabled.
> > /proc/cpuinfo is normal as per HT, displaying 4 cpus.
>
> you should run the userspace irq balance daemon:
> http://people.redhat.com/arjanv/irqbalance/
I have long wondered what is so evil about most interrupts going to
CPU 0 that we felt we had to have a pair of irqdaemons in 2.6. From my
(admittedly imperfect) experience, the APIC will route an interrupt to
CPU 1 if CPU 0 is busy with another interrupt, to CPU 2 if 0 and 1 are
so occupied, and so on. I see no harm in this other than the strangely
lopsided /proc/interrupt displays, which I can live with.
Earlier APICs had a variation where the search for where each new
interrupt was to go started with first cpu after the one that got the
last interrupt. If we call this 'round-robin' allocation, then today's
technique could be described as 'first fit'.
If I am wrong about this, I would dearly love to be corrected :)
Joe
next prev parent reply other threads:[~2004-01-11 16:50 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-01-10 23:14 2.6.1 and irq balancing Ethan Weinstein
2004-01-11 2:39 ` Ed Tomlinson
2004-01-11 3:38 ` Nick Piggin
2004-01-11 9:52 ` Arjan van de Ven
2004-01-11 5:19 ` Ethan Weinstein
2004-01-11 9:51 ` Arjan van de Ven
2004-01-11 16:50 ` Joe Korty [this message]
2004-01-11 18:19 ` Arjan van de Ven
2004-01-15 11:43 ` Pavel Machek
2004-01-11 13:14 ` Martin Schlemmer
2004-01-11 23:59 Nakajima, Jun
2004-01-12 4:42 ` Bill Davidsen
2004-01-12 14:06 ` Zwane Mwaikambo
2004-01-12 16:10 ` Martin J. Bligh
2004-01-13 6:50 ` Ethan Weinstein
2004-01-13 7:05 ` Nick Piggin
2004-01-13 7:57 Nakajima, Jun
2004-01-13 8:09 Nakajima, Jun
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20040111165012.GA24746@tsunami.ccur.com \
--to=joe.korty@ccur.com \
--cc=arjanv@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=lists@stinkfoot.org \
--cc=wli@holomorphy.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).