From: Mark Lord <lkml@rtr.ca>
To: Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@osdl.org>, Ingo Molnar <mingo@elte.hu>,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: CONFIG_IRQBALANCE for 64-bit x86 ?
Date: Mon, 19 Nov 2007 23:12:21 -0500 [thread overview]
Message-ID: <47425EA5.7000607@rtr.ca> (raw)
On 32-bit x86, we have CONFIG_IRQBALANCE available,
but not on 64-bit x86. Why not?
I ask, because this feature seems almost essential to obtaining
reasonable latencies during heavy I/O with fast devices.
My 32-bit Core2Duo MythTV box drops audio frames without it,
but works perfectly *with* IRQBALANCE.
My QuadCore box works very well in 32-bit mode with IRQBALANCE,
but responsiveness sucks bigtime when run in 64-bit mode (no IRQBALANCE)
during periods of multiple heavy I/O streams (USB flash drives).
That's with both the 32 and 64 bit versions of Kubuntu Gutsy,
so the software uses pretty much identical versions either way.
As near as I can tell, when IRQBALANCE is not configured,
all I/O device interrupts go to CPU#0.
I don't think our CPU scheduler takes that into account when assigning
tasks to CPUs, so anything sent to CPU0 runs with very high latencies.
Or something like that.
Why no IRQ_BALANCE in 64-bit mode ?
next reply other threads:[~2007-11-20 4:12 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-20 4:12 Mark Lord [this message]
2007-11-20 4:15 ` CONFIG_IRQBALANCE for 64-bit x86 ? Ismail Dönmez
2007-11-20 4:17 ` Nick Piggin
2007-11-20 4:29 ` Willy Tarreau
2007-11-20 4:37 ` Adrian Bunk
2007-11-20 5:24 ` Nick Piggin
2007-11-20 5:28 ` H. Peter Anvin
2007-11-20 5:37 ` Arjan van de Ven
2007-11-20 7:37 ` Nick Piggin
2007-11-20 14:47 ` Arjan van de Ven
2007-11-20 15:43 ` Nick Piggin
2007-11-20 19:07 ` Arjan van de Ven
2007-11-20 20:02 ` Mark Lord
2007-11-20 21:58 ` Arjan van de Ven
2007-11-20 23:17 ` Mark Lord
2007-11-22 7:54 ` Nick Piggin
2007-11-23 13:09 ` Ingo Molnar
2007-11-25 10:03 ` Nick Piggin
2007-11-20 15:47 ` Mark Lord
2007-11-20 15:52 ` Mark Lord
2007-11-20 16:02 ` Arjan van de Ven
2007-11-20 16:10 ` Mark Lord
2007-11-20 18:42 ` Mark Lord
2007-11-20 22:01 ` Ingo Molnar
2007-11-20 23:22 ` Mark Lord
2007-11-20 23:27 ` Ingo Molnar
2007-11-20 23:33 ` H. Peter Anvin
2007-11-20 23:47 ` Ingo Molnar
2007-11-20 23:50 ` H. Peter Anvin
2007-11-21 0:07 ` Ingo Molnar
2007-11-21 0:20 ` H. Peter Anvin
2007-11-21 0:36 ` Ingo Molnar
2007-11-21 0:47 ` H. Peter Anvin
2007-11-21 2:48 ` Jeff Garzik
2007-11-21 2:59 ` H. Peter Anvin
2007-11-20 23:28 ` H. Peter Anvin
2007-11-20 19:17 ` Andi Kleen
-- strict thread matches above, loose matches on Subject: below --
2007-11-21 2:22 Walt H
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=47425EA5.7000607@rtr.ca \
--to=lkml@rtr.ca \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=torvalds@osdl.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.