From: Gilad Ben-Yossef <gilad@benyossef.com>
To: Christoph Lameter <cl@linux.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Avi Kivity <avi@redhat.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
linux-kernel@vger.kernel.org, Chris Metcalf <cmetcalf@tilera.com>,
Frederic Weisbecker <fweisbec@gmail.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>,
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: Sun, 5 Feb 2012 14:06:29 +0200 [thread overview]
Message-ID: <CAOtvUMdCZpQuSvutKHpMxthktTm_VkA1R99yxpNhxpsYN9wTRQ@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1202021124520.6338@router.home>
On Thu, Feb 2, 2012 at 7:25 PM, Christoph Lameter <cl@linux.com> wrote:
> On Thu, 2 Feb 2012, Paul E. McKenney wrote:
>
>> Frederic's work checks to see if there is only one runnable user task
>> on a given CPU. If there is only one, then the scheduling-clock interrupt
>> is turned off for that CPU, and RCU is told to ignore it while it is
>> executing in user space. Not sure whether this covers KVM guests.
>>
>> In any case, this is not yet in mainline.
>
> Sounds great. Is there any plan on when to merge it? Where are the most up
> to date patches vs mainstream?
>
Frederic has the latest version in a git tree here:
git://github.com/fweisbec/linux-dynticks.git
nohz/cpuset-v2-pre-20120117
It's on top latest rcu/core.
I've been playing with it for some time now. It works very well, considering the
early state - there are a couple of TODO items listed here:
https://tglx.de/~fweisbec/TODO-nohz-cpusets and I've seen an assert from
the RCU code once.
Also, there is some system stuff "in the way" so to speak, of getting the full
benefits:
I had to disable the clock source watchdog (I'm testing in a KVM VM, so I guess
the TSC is not stable), the vmstat_stats work on that CPU and to (try
to) fix what
looks like a bug in the NOHZ timer code.
But the good news is that with these hacks applied I managed to run a 100%
CPU task with zero interrupts (ticks or otherwise) on an isolated cpu.
Disregarding TLB overhead, you get bare metal performance with Linux user
space manageability and debug capabilities. Pretty magical really: It's like
eating your cake and having it too :-)
Gilad
--
Gilad Ben-Yossef
Chief Coffee Drinker
gilad@benyossef.com
http://benyossef.com
"If you take a class in large-scale robotics, can you end up in a
situation where the homework eats your dog?"
-- Jean-Baptiste Queru
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2012-02-05 12:06 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
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
2012-01-29 12:24 ` Gilad Ben-Yossef
2012-01-30 21:52 ` Andrew Morton
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 ` [v7 3/8] tile: move tile to use " Gilad Ben-Yossef
2012-01-26 10:01 ` [v7 4/8] smp: add func to IPI cpus based on parameter func Gilad Ben-Yossef
2012-01-27 23:57 ` Andrew Morton
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 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 10:02 ` [v7 7/8] mm: only IPI CPUs to drain local pages if they exist Gilad Ben-Yossef
2012-01-26 15:13 ` Christoph Lameter
2012-01-28 0:12 ` Andrew Morton
2012-01-29 12:18 ` Gilad Ben-Yossef
2012-01-30 21:49 ` Andrew Morton
2012-01-31 6:32 ` Gilad Ben-Yossef
2012-01-30 14:59 ` Mel Gorman
2012-01-30 15:14 ` Gilad Ben-Yossef
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 15:19 ` [v7 0/8] Reduce cross CPU IPI interference Peter Zijlstra
2012-01-29 8:25 ` Gilad Ben-Yossef
2012-02-01 17:04 ` Frederic Weisbecker
2012-02-02 8:46 ` Gilad Ben-Yossef
2012-02-02 15:41 ` Chris Metcalf
2012-02-05 11:46 ` Gilad Ben-Yossef
2012-02-10 18:39 ` Peter Zijlstra
2012-02-10 20:13 ` Gilad Ben-Yossef
2012-02-10 20:29 ` Peter Zijlstra
2012-02-10 20:39 ` Gilad Ben-Yossef
2012-02-10 18:33 ` Peter Zijlstra
2012-02-10 20:33 ` Gilad Ben-Yossef
2012-02-15 21:50 ` Chris Metcalf
2012-02-15 22:15 ` Christoph Lameter
2012-02-15 23:44 ` Chris Metcalf
2012-02-21 1:34 ` Frederic Weisbecker
2012-03-01 18:27 ` Chris Metcalf
2012-02-10 18:38 ` Peter Zijlstra
2012-02-10 20:24 ` Gilad Ben-Yossef
2012-02-15 15:11 ` Peter Zijlstra
2012-02-15 15:19 ` Gilad Ben-Yossef
2012-02-15 21:51 ` Chris Metcalf
2012-02-02 16:24 ` Frederic Weisbecker
2012-02-02 16:29 ` Christoph Lameter
2012-02-09 15:52 ` Frederic Weisbecker
2012-02-09 15:59 ` Chris Metcalf
2012-02-09 18:11 ` Frederic Weisbecker
2012-02-09 16:26 ` Christoph Lameter
2012-02-09 18:32 ` Frederic Weisbecker
2012-02-01 17:35 ` Peter Zijlstra
2012-02-01 17:57 ` Peter Zijlstra
2012-02-02 9:42 ` Gilad Ben-Yossef
2012-02-01 18:40 ` Paul E. McKenney
2012-02-01 20:06 ` Christoph Lameter
2012-02-01 20:13 ` Paul E. McKenney
2012-02-02 9:34 ` Avi Kivity
2012-02-02 15:34 ` Paul E. McKenney
2012-02-02 16:14 ` Avi Kivity
2012-02-02 17:01 ` Paul E. McKenney
2012-02-02 17:23 ` Avi Kivity
2012-02-02 17:51 ` Paul E. McKenney
2012-02-05 12:16 ` Avi Kivity
2012-02-05 16:59 ` Paul E. McKenney
2012-02-09 15:22 ` Frederic Weisbecker
2012-02-09 16:05 ` Avi Kivity
2012-02-09 18:22 ` Frederic Weisbecker
2012-02-09 23:41 ` Paul E. McKenney
2012-02-10 1:39 ` Frederic Weisbecker
2012-02-14 13:18 ` Avi Kivity
2012-02-21 0:02 ` Frederic Weisbecker
2012-02-02 17:25 ` Christoph Lameter
2012-02-05 12:06 ` Gilad Ben-Yossef [this message]
2012-02-06 18:19 ` Christoph Lameter
2012-02-09 15:37 ` Frederic Weisbecker
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=CAOtvUMdCZpQuSvutKHpMxthktTm_VkA1R99yxpNhxpsYN9wTRQ@mail.gmail.com \
--to=gilad@benyossef.com \
--cc=a.p.zijlstra@chello.nl \
--cc=akpm@linux-foundation.org \
--cc=andi@firstfloor.org \
--cc=avi@redhat.com \
--cc=cl@linux.com \
--cc=cmetcalf@tilera.com \
--cc=fweisbec@gmail.com \
--cc=kosaki.motohiro@gmail.com \
--cc=levinsasha928@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mel@csn.ul.ie \
--cc=miltonm@bga.com \
--cc=mina86@mina86.com \
--cc=mpm@selenic.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=penberg@kernel.org \
--cc=riel@redhat.com \
--cc=viro@zeniv.linux.org.uk \
/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