From: Jamie Lokier <jamie@shareable.org>
To: Miquel van Smoorenburg <miquels@cistron.nl>
Cc: linux-kernel@vger.kernel.org
Subject: Re: arch/i386/Kconfig: CONFIG_IRQBALANCE Description
Date: Thu, 25 Mar 2004 19:07:18 +0000 [thread overview]
Message-ID: <20040325190718.GD11236@mail.shareable.org> (raw)
In-Reply-To: <c3qa94$qhi$1@news.cistron.nl>
Miquel van Smoorenburg wrote:
> Is that real SMP, or hyperthreading? If it's hyperthreading, then
> it makes sense that the IRQs are not balanced.
That's unfair to the two tasks which might be running on each virtual
CPU: one of the tasks is interrupted often.
> In fact I have a server on which the IRQ balancing code does
> balance over the 2 virtual CPUs by accident (still have to debug
> what goes wrong and file a proper bug report) and as a result
> performance sucked until I turned it off.
What caused the suckage? Obviously there's a small time spend doing
the work of rebalancing, but there is no cache hit from moving an
interrupt between virtual CPUs, unlike with SMP, so why did that make
performance suck?
-- Jamie
next prev parent reply other threads:[~2004-03-25 19:07 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-22 23:02 arch/i386/Kconfig: CONFIG_IRQBALANCE Description Rusty Russell
2004-03-23 17:16 ` John Stoffel
2004-03-23 21:30 ` Miquel van Smoorenburg
2004-03-24 14:04 ` John Stoffel
2004-03-25 19:07 ` Jamie Lokier [this message]
2004-03-26 10:39 ` Miquel van Smoorenburg
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=20040325190718.GD11236@mail.shareable.org \
--to=jamie@shareable.org \
--cc=linux-kernel@vger.kernel.org \
--cc=miquels@cistron.nl \
/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