From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Chris Metcalf <cmetcalf@tilera.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Gilad Ben-Yossef <gilad@benyossef.com>,
linux-kernel@vger.kernel.org, Christoph Lameter <cl@linux.com>,
linux-mm@kvack.org, Pekka Enberg <penberg@kernel.org>,
Matt Mackall <mpm@selenic.com>,
Sasha Levin <levinsasha928@gmail.com>,
Rik van Riel <riel@redhat.com>, Andi Kleen <andi@firstfloor.org>,
Mel Gorman <mel@csn.ul.ie>,
Andrew Morton <akpm@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Avi Kivity <avi@redhat.com>,
Michal Nazarewicz <mina86@mina86.com>,
Kosaki Motohiro <kosaki.motohiro@gmail.com>,
Milton Miller <miltonm@bga.com>
Subject: Re: [v7 0/8] Reduce cross CPU IPI interference
Date: Fri, 10 Feb 2012 19:33:36 +0100 [thread overview]
Message-ID: <1328898816.25989.33.camel@laptop> (raw)
In-Reply-To: <4F2AAEB9.9070302@tilera.com>
On Thu, 2012-02-02 at 10:41 -0500, Chris Metcalf wrote:
> At Tilera we have been supporting a "dataplane" mode (aka Zero Overhead
> Linux - the marketing name). This is configured on a per-cpu basis, and in
> addition to setting isolcpus for those nodes, also suppresses various
> things that might otherwise run (soft lockup detection, vmstat work,
> etc.).
See that's wrong.. it starts being wrong by depending on cpuisol and
goes from there.
> The claim is that you need to specify these kinds of things
> per-core since it's not always possible for the kernel to know that you
> really don't want the scheduler or any other interrupt source to touch the
> core, as opposed to the case where you just happen to have a single process
> scheduled on the core and you don't mind occasional interrupts.
Right, so that claim is proven false I think.
> But
> there's definitely appeal in having the kernel do it adaptively too,
> particularly if it can be made to work just as well as configuring it
> statically.
I see no reason why it shouldn't work as well or even better.
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WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Chris Metcalf <cmetcalf@tilera.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Gilad Ben-Yossef <gilad@benyossef.com>,
linux-kernel@vger.kernel.org, Christoph Lameter <cl@linux.com>,
linux-mm@kvack.org, Pekka Enberg <penberg@kernel.org>,
Matt Mackall <mpm@selenic.com>,
Sasha Levin <levinsasha928@gmail.com>,
Rik van Riel <riel@redhat.com>, Andi Kleen <andi@firstfloor.org>,
Mel Gorman <mel@csn.ul.ie>,
Andrew Morton <akpm@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Avi Kivity <avi@redhat.com>,
Michal Nazarewicz <mina86@mina86.com>,
Kosaki Motohiro <kosaki.motohiro@gmail.com>,
Milton Miller <miltonm@bga.com>
Subject: Re: [v7 0/8] Reduce cross CPU IPI interference
Date: Fri, 10 Feb 2012 19:33:36 +0100 [thread overview]
Message-ID: <1328898816.25989.33.camel@laptop> (raw)
In-Reply-To: <4F2AAEB9.9070302@tilera.com>
On Thu, 2012-02-02 at 10:41 -0500, Chris Metcalf wrote:
> At Tilera we have been supporting a "dataplane" mode (aka Zero Overhead
> Linux - the marketing name). This is configured on a per-cpu basis, and in
> addition to setting isolcpus for those nodes, also suppresses various
> things that might otherwise run (soft lockup detection, vmstat work,
> etc.).
See that's wrong.. it starts being wrong by depending on cpuisol and
goes from there.
> The claim is that you need to specify these kinds of things
> per-core since it's not always possible for the kernel to know that you
> really don't want the scheduler or any other interrupt source to touch the
> core, as opposed to the case where you just happen to have a single process
> scheduled on the core and you don't mind occasional interrupts.
Right, so that claim is proven false I think.
> But
> there's definitely appeal in having the kernel do it adaptively too,
> particularly if it can be made to work just as well as configuring it
> statically.
I see no reason why it shouldn't work as well or even better.
next prev parent reply other threads:[~2012-02-10 18:33 UTC|newest]
Thread overview: 154+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-26 10:01 [v7 0/8] Reduce cross CPU IPI interference Gilad Ben-Yossef
2012-01-26 10:01 ` Gilad Ben-Yossef
2012-01-26 10:01 ` [v7 1/8] smp: introduce a generic on_each_cpu_mask function Gilad Ben-Yossef
2012-01-26 10:01 ` Gilad Ben-Yossef
2012-01-29 12:24 ` Gilad Ben-Yossef
2012-01-29 12:24 ` Gilad Ben-Yossef
2012-01-30 21:52 ` Andrew Morton
2012-01-30 21:52 ` Andrew Morton
2012-01-31 6:33 ` Gilad Ben-Yossef
2012-01-31 6:33 ` Gilad Ben-Yossef
2012-01-26 10:01 ` [v7 2/8] arm: move arm over to generic on_each_cpu_mask Gilad Ben-Yossef
2012-01-26 10:01 ` Gilad Ben-Yossef
2012-01-26 10:01 ` [v7 3/8] tile: move tile to use " Gilad Ben-Yossef
2012-01-26 10:01 ` Gilad Ben-Yossef
2012-01-26 10:01 ` [v7 4/8] smp: add func to IPI cpus based on parameter func Gilad Ben-Yossef
2012-01-26 10:01 ` Gilad Ben-Yossef
2012-01-27 23:57 ` Andrew Morton
2012-01-27 23:57 ` Andrew Morton
2012-01-29 12:04 ` Gilad Ben-Yossef
2012-01-29 12:04 ` Gilad Ben-Yossef
2012-01-26 10:01 ` [v7 5/8] slub: only IPI CPUs that have per cpu obj to flush Gilad Ben-Yossef
2012-01-26 10:01 ` Gilad Ben-Yossef
2012-01-26 15:09 ` Christoph Lameter
2012-01-26 15:09 ` Christoph Lameter
2012-01-26 10:01 ` [v7 6/8] fs: only send IPI to invalidate LRU BH when needed Gilad Ben-Yossef
2012-01-26 10:01 ` Gilad Ben-Yossef
2012-01-26 10:02 ` [v7 7/8] mm: only IPI CPUs to drain local pages if they exist Gilad Ben-Yossef
2012-01-26 10:02 ` Gilad Ben-Yossef
2012-01-26 15:13 ` Christoph Lameter
2012-01-26 15:13 ` Christoph Lameter
2012-01-28 0:12 ` Andrew Morton
2012-01-28 0:12 ` Andrew Morton
2012-01-29 12:18 ` Gilad Ben-Yossef
2012-01-29 12:18 ` Gilad Ben-Yossef
2012-01-30 21:49 ` Andrew Morton
2012-01-30 21:49 ` Andrew Morton
2012-01-31 6:32 ` Gilad Ben-Yossef
2012-01-31 6:32 ` Gilad Ben-Yossef
2012-01-30 14:59 ` Mel Gorman
2012-01-30 14:59 ` Mel Gorman
2012-01-30 15:14 ` Gilad Ben-Yossef
2012-01-30 15:14 ` Gilad Ben-Yossef
2012-01-30 15:44 ` Mel Gorman
2012-01-30 15:44 ` Mel Gorman
2012-01-30 15:44 ` Mel Gorman
2012-01-26 10:02 ` [v7 8/8] mm: add vmstat counters for tracking PCP drains Gilad Ben-Yossef
2012-01-26 10:02 ` Gilad Ben-Yossef
2012-01-26 15:19 ` [v7 0/8] Reduce cross CPU IPI interference Peter Zijlstra
2012-01-26 15:19 ` Peter Zijlstra
2012-01-29 8:25 ` Gilad Ben-Yossef
2012-01-29 8:25 ` Gilad Ben-Yossef
2012-02-01 17:04 ` Frederic Weisbecker
2012-02-01 17:04 ` Frederic Weisbecker
2012-02-02 8:46 ` Gilad Ben-Yossef
2012-02-02 8:46 ` Gilad Ben-Yossef
2012-02-02 15:41 ` Chris Metcalf
2012-02-02 15:41 ` Chris Metcalf
2012-02-05 11:46 ` Gilad Ben-Yossef
2012-02-05 11:46 ` Gilad Ben-Yossef
2012-02-10 18:39 ` Peter Zijlstra
2012-02-10 18:39 ` Peter Zijlstra
2012-02-10 20:13 ` Gilad Ben-Yossef
2012-02-10 20:13 ` Gilad Ben-Yossef
2012-02-10 20:29 ` Peter Zijlstra
2012-02-10 20:29 ` Peter Zijlstra
2012-02-10 20:39 ` Gilad Ben-Yossef
2012-02-10 20:39 ` Gilad Ben-Yossef
2012-02-10 18:33 ` Peter Zijlstra [this message]
2012-02-10 18:33 ` Peter Zijlstra
2012-02-10 20:33 ` Gilad Ben-Yossef
2012-02-10 20:33 ` Gilad Ben-Yossef
2012-02-15 21:50 ` Chris Metcalf
2012-02-15 21:50 ` Chris Metcalf
2012-02-15 22:15 ` Christoph Lameter
2012-02-15 22:15 ` Christoph Lameter
2012-02-15 23:44 ` Chris Metcalf
2012-02-15 23:44 ` Chris Metcalf
2012-02-21 1:34 ` Frederic Weisbecker
2012-02-21 1:34 ` Frederic Weisbecker
2012-03-01 18:27 ` Chris Metcalf
2012-03-01 18:27 ` Chris Metcalf
2012-02-10 18:38 ` Peter Zijlstra
2012-02-10 18:38 ` Peter Zijlstra
2012-02-10 20:24 ` Gilad Ben-Yossef
2012-02-10 20:24 ` Gilad Ben-Yossef
2012-02-15 15:11 ` Peter Zijlstra
2012-02-15 15:11 ` Peter Zijlstra
2012-02-15 15:19 ` Gilad Ben-Yossef
2012-02-15 15:19 ` Gilad Ben-Yossef
2012-02-15 21:51 ` Chris Metcalf
2012-02-15 21:51 ` Chris Metcalf
2012-02-02 16:24 ` Frederic Weisbecker
2012-02-02 16:24 ` Frederic Weisbecker
2012-02-02 16:29 ` Christoph Lameter
2012-02-09 15:52 ` Frederic Weisbecker
2012-02-09 15:52 ` Frederic Weisbecker
2012-02-09 15:59 ` Chris Metcalf
2012-02-09 15:59 ` Chris Metcalf
2012-02-09 18:11 ` Frederic Weisbecker
2012-02-09 18:11 ` Frederic Weisbecker
2012-02-09 16:26 ` Christoph Lameter
2012-02-09 16:26 ` Christoph Lameter
2012-02-09 18:32 ` Frederic Weisbecker
2012-02-09 18:32 ` Frederic Weisbecker
2012-02-01 17:35 ` Peter Zijlstra
2012-02-01 17:35 ` Peter Zijlstra
2012-02-01 17:57 ` Peter Zijlstra
2012-02-01 17:57 ` Peter Zijlstra
2012-02-02 9:42 ` Gilad Ben-Yossef
2012-02-02 9:42 ` Gilad Ben-Yossef
2012-02-01 18:40 ` Paul E. McKenney
2012-02-01 18:40 ` Paul E. McKenney
2012-02-01 20:06 ` Christoph Lameter
2012-02-01 20:06 ` Christoph Lameter
2012-02-01 20:13 ` Paul E. McKenney
2012-02-01 20:13 ` Paul E. McKenney
2012-02-02 9:34 ` Avi Kivity
2012-02-02 9:34 ` Avi Kivity
2012-02-02 15:34 ` Paul E. McKenney
2012-02-02 15:34 ` Paul E. McKenney
2012-02-02 16:14 ` Avi Kivity
2012-02-02 16:14 ` Avi Kivity
2012-02-02 17:01 ` Paul E. McKenney
2012-02-02 17:01 ` Paul E. McKenney
2012-02-02 17:23 ` Avi Kivity
2012-02-02 17:23 ` Avi Kivity
2012-02-02 17:51 ` Paul E. McKenney
2012-02-02 17:51 ` Paul E. McKenney
2012-02-05 12:16 ` Avi Kivity
2012-02-05 12:16 ` Avi Kivity
2012-02-05 16:59 ` Paul E. McKenney
2012-02-05 16:59 ` Paul E. McKenney
2012-02-09 15:22 ` Frederic Weisbecker
2012-02-09 15:22 ` Frederic Weisbecker
2012-02-09 16:05 ` Avi Kivity
2012-02-09 16:05 ` Avi Kivity
2012-02-09 18:22 ` Frederic Weisbecker
2012-02-09 18:22 ` Frederic Weisbecker
2012-02-09 23:41 ` Paul E. McKenney
2012-02-09 23:41 ` Paul E. McKenney
2012-02-10 1:39 ` Frederic Weisbecker
2012-02-10 1:39 ` Frederic Weisbecker
2012-02-14 13:18 ` Avi Kivity
2012-02-14 13:18 ` Avi Kivity
2012-02-21 0:02 ` Frederic Weisbecker
2012-02-21 0:02 ` Frederic Weisbecker
2012-02-02 17:25 ` Christoph Lameter
2012-02-02 17:25 ` Christoph Lameter
2012-02-05 12:06 ` Gilad Ben-Yossef
2012-02-05 12:06 ` Gilad Ben-Yossef
2012-02-06 18:19 ` Christoph Lameter
2012-02-06 18:19 ` Christoph Lameter
2012-02-09 15:37 ` Frederic Weisbecker
2012-02-09 15:37 ` Frederic Weisbecker
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