From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Waiman Long <Waiman.Long@hp.com>, Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Rik van Riel <riel@redhat.com>,
Peter Hurley <peter@hurleysoftware.com>,
Davidlohr Bueso <davidlohr.bueso@hp.com>,
Alex Shi <alex.shi@intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Matthew R Wilcox <matthew.r.wilcox@intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Michel Lespinasse <walken@google.com>,
Andi Kleen <andi@firstfloor.org>,
"Chandramouleeswaran, Aswin" <aswin@hp.com>,
"Norton, Scott J" <scott.norton@hp.com>
Subject: Re: [PATCH] rwsem: reduce spinlock contention in wakeup code path
Date: Tue, 1 Oct 2013 09:48:02 +0200 [thread overview]
Message-ID: <20131001074802.GB20889@gmail.com> (raw)
In-Reply-To: <20130930104658.GX3081@twins.programming.kicks-ass.net>
* Peter Zijlstra <peterz@infradead.org> wrote:
> On Sat, Sep 28, 2013 at 11:55:26AM -0700, Linus Torvalds wrote:
> > So if the primary reason for this is really just that f*cking anon_vma
> > lock, then I would seriously suggest:
>
> I would still like to see the rwsem patches merged; even if we end up
> going back to a spin style anon_vma lock.
>
> There's been various reports in the past about how programs are
> significantly faster if they wrap their mmap() calls in a pthread_mutex.
> And this was purely down to the fact that rwsem writer-writer contention
> blows chunks.
That's about the mm->mmap_sem rwsem, right?
That impact would have to be measured carefully, and not just for
workloads where we know that better contention logic helps, but other MM
workloads that are hitting hard on mmap_sem.
Thanks,
Ingo
next prev parent reply other threads:[~2013-10-01 7:48 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-27 19:00 [PATCH] rwsem: reduce spinlock contention in wakeup code path Waiman Long
2013-09-27 19:28 ` Linus Torvalds
2013-09-27 19:39 ` Davidlohr Bueso
2013-09-27 21:49 ` Tim Chen
2013-09-28 6:45 ` Ingo Molnar
2013-09-28 7:41 ` Ingo Molnar
2013-09-28 18:55 ` Linus Torvalds
2013-09-28 19:13 ` Andi Kleen
2013-09-28 19:22 ` Linus Torvalds
2013-09-28 19:21 ` Ingo Molnar
2013-09-28 19:33 ` Linus Torvalds
2013-09-28 19:39 ` Ingo Molnar
2013-09-30 10:44 ` Peter Zijlstra
2013-09-30 16:13 ` Linus Torvalds
2013-09-30 16:41 ` Peter Zijlstra
2013-10-01 7:28 ` Ingo Molnar
2013-10-01 8:09 ` Peter Zijlstra
2013-10-01 8:25 ` Ingo Molnar
2013-09-30 15:58 ` Waiman Long
2013-10-01 7:33 ` Ingo Molnar
2013-10-01 20:03 ` Waiman Long
2013-09-28 19:37 ` [PATCH] anon_vmas: Convert the rwsem to an rwlock_t Ingo Molnar
2013-09-28 19:43 ` Linus Torvalds
2013-09-28 19:46 ` Ingo Molnar
2013-09-28 19:52 ` [PATCH, v2] " Ingo Molnar
2013-09-30 11:00 ` Peter Zijlstra
2013-09-30 11:44 ` Peter Zijlstra
2013-09-30 17:03 ` Andrew Morton
2013-09-30 17:25 ` Linus Torvalds
2013-09-30 17:10 ` Tim Chen
2013-09-30 18:14 ` Peter Zijlstra
2013-09-30 19:23 ` Tim Chen
2013-09-30 19:35 ` Waiman Long
2013-09-30 19:47 ` Tim Chen
2013-09-30 22:03 ` Tim Chen
2013-10-01 2:41 ` Waiman Long
2013-09-30 8:52 ` [PATCH] " Andrea Arcangeli
2013-09-30 14:40 ` Jerome Glisse
2013-09-30 16:26 ` Linus Torvalds
2013-09-30 19:16 ` Andrea Arcangeli
2013-09-30 18:21 ` Andi Kleen
2013-09-30 19:04 ` Jerome Glisse
2013-09-29 23:06 ` [PATCH] rwsem: reduce spinlock contention in wakeup code path Davidlohr Bueso
2013-09-29 23:26 ` Linus Torvalds
2013-09-30 0:40 ` Davidlohr Bueso
2013-09-30 0:51 ` Linus Torvalds
2013-09-30 6:57 ` Ingo Molnar
2013-09-30 1:11 ` Michel Lespinasse
2013-09-30 7:05 ` Ingo Molnar
2013-09-30 16:03 ` Waiman Long
2013-09-30 10:46 ` Peter Zijlstra
2013-10-01 7:48 ` Ingo Molnar [this message]
2013-10-01 8:10 ` Peter Zijlstra
2013-09-27 19:32 ` Peter Hurley
2013-09-28 0:46 ` Waiman Long
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