From: Andi Kleen <ak@linux.intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
"Liang, Kan" <kan.liang@intel.com>,
Mel Gorman <mgorman@techsingularity.net>,
Mel Gorman <mgorman@suse.de>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>, Jan Kara <jack@suse.cz>,
linux-mm <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] sched/wait: Break up long wake list walk
Date: Tue, 22 Aug 2017 12:37:14 -0700 [thread overview]
Message-ID: <20170822193714.GZ28715@tassilo.jf.intel.com> (raw)
In-Reply-To: <CA+55aFzPt401xpRzd6Qu-WuDNGneR_m7z25O=0YspNi+cLRb8w@mail.gmail.com>
> > Still, generating such a migration storm would be fairly tricky I think.
>
> Well, Mel seems to have been unable to generate a load that reproduces
> the long page waitqueues. And I don't think we've had any other
> reports of this either.
It could be that it requires a fairly large system. On large systems
under load a lot of things take much longer, so what's a tiny window on Mel's
system may suddenly be very large, and with much more threads
they have a higher chance of bad interactions anyways.
We only see it on 4S+ today. But systems are always getting larger,
so what's a large system today, will be a normal medium scale system
tomorrow.
BTW we also collected PT traces for the long hang cases, but it was
hard to find a consistent pattern in them.
-Andi
WARNING: multiple messages have this Message-ID (diff)
From: Andi Kleen <ak@linux.intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
"Liang, Kan" <kan.liang@intel.com>,
Mel Gorman <mgorman@techsingularity.net>,
Mel Gorman <mgorman@suse.de>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>, Jan Kara <jack@suse.cz>,
linux-mm <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] sched/wait: Break up long wake list walk
Date: Tue, 22 Aug 2017 12:37:14 -0700 [thread overview]
Message-ID: <20170822193714.GZ28715@tassilo.jf.intel.com> (raw)
In-Reply-To: <CA+55aFzPt401xpRzd6Qu-WuDNGneR_m7z25O=0YspNi+cLRb8w@mail.gmail.com>
> > Still, generating such a migration storm would be fairly tricky I think.
>
> Well, Mel seems to have been unable to generate a load that reproduces
> the long page waitqueues. And I don't think we've had any other
> reports of this either.
It could be that it requires a fairly large system. On large systems
under load a lot of things take much longer, so what's a tiny window on Mel's
system may suddenly be very large, and with much more threads
they have a higher chance of bad interactions anyways.
We only see it on 4S+ today. But systems are always getting larger,
so what's a large system today, will be a normal medium scale system
tomorrow.
BTW we also collected PT traces for the long hang cases, but it was
hard to find a consistent pattern in them.
-Andi
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next prev parent reply other threads:[~2017-08-22 19:37 UTC|newest]
Thread overview: 121+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-15 0:52 [PATCH 1/2] sched/wait: Break up long wake list walk Tim Chen
2017-08-15 0:52 ` Tim Chen
2017-08-15 0:52 ` [PATCH 2/2] sched/wait: Introduce lock breaker in wake_up_page_bit Tim Chen
2017-08-15 0:52 ` Tim Chen
2017-08-15 1:48 ` [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds
2017-08-15 1:48 ` Linus Torvalds
2017-08-15 2:27 ` Andi Kleen
2017-08-15 2:27 ` Andi Kleen
2017-08-15 2:52 ` Linus Torvalds
2017-08-15 2:52 ` Linus Torvalds
2017-08-15 3:15 ` Andi Kleen
2017-08-15 3:15 ` Andi Kleen
2017-08-15 3:28 ` Linus Torvalds
2017-08-15 3:28 ` Linus Torvalds
2017-08-15 19:05 ` Tim Chen
2017-08-15 19:05 ` Tim Chen
2017-08-15 19:41 ` Linus Torvalds
2017-08-15 19:41 ` Linus Torvalds
2017-08-15 19:47 ` Linus Torvalds
2017-08-15 19:47 ` Linus Torvalds
2017-08-15 22:47 ` Davidlohr Bueso
2017-08-15 22:47 ` Davidlohr Bueso
2017-08-15 22:56 ` Linus Torvalds
2017-08-15 22:56 ` Linus Torvalds
2017-08-15 22:57 ` Linus Torvalds
2017-08-15 22:57 ` Linus Torvalds
2017-08-15 23:50 ` Linus Torvalds
2017-08-15 23:50 ` Linus Torvalds
2017-08-16 23:22 ` Eric W. Biederman
2017-08-16 23:22 ` Eric W. Biederman
2017-08-17 16:17 ` Liang, Kan
2017-08-17 16:17 ` Liang, Kan
2017-08-17 16:25 ` Linus Torvalds
2017-08-17 16:25 ` Linus Torvalds
2017-08-17 20:18 ` Liang, Kan
2017-08-17 20:44 ` Linus Torvalds
2017-08-17 20:44 ` Linus Torvalds
2017-08-18 12:23 ` Mel Gorman
2017-08-18 12:23 ` Mel Gorman
2017-08-18 14:20 ` Liang, Kan
2017-08-18 14:20 ` Liang, Kan
2017-08-18 14:46 ` Mel Gorman
2017-08-18 14:46 ` Mel Gorman
2017-08-18 16:36 ` Tim Chen
2017-08-18 16:36 ` Tim Chen
2017-08-18 16:45 ` Andi Kleen
2017-08-18 16:45 ` Andi Kleen
2017-08-18 16:53 ` Liang, Kan
2017-08-18 16:53 ` Liang, Kan
2017-08-18 17:48 ` Linus Torvalds
2017-08-18 17:48 ` Linus Torvalds
2017-08-18 18:54 ` Mel Gorman
2017-08-18 18:54 ` Mel Gorman
2017-08-18 19:14 ` Linus Torvalds
2017-08-18 19:58 ` Andi Kleen
2017-08-18 19:58 ` Andi Kleen
2017-08-18 20:10 ` Linus Torvalds
2017-08-18 20:10 ` Linus Torvalds
2017-08-21 18:32 ` Mel Gorman
2017-08-21 18:32 ` Mel Gorman
2017-08-21 18:56 ` Liang, Kan
2017-08-21 18:56 ` Liang, Kan
2017-08-22 17:23 ` Liang, Kan
2017-08-22 17:23 ` Liang, Kan
2017-08-22 18:19 ` Linus Torvalds
2017-08-22 18:25 ` Linus Torvalds
2017-08-22 18:25 ` Linus Torvalds
2017-08-22 18:56 ` Peter Zijlstra
2017-08-22 18:56 ` Peter Zijlstra
2017-08-22 19:15 ` Linus Torvalds
2017-08-22 19:15 ` Linus Torvalds
2017-08-22 19:08 ` Peter Zijlstra
2017-08-22 19:08 ` Peter Zijlstra
2017-08-22 19:30 ` Linus Torvalds
2017-08-22 19:30 ` Linus Torvalds
2017-08-22 19:37 ` Andi Kleen [this message]
2017-08-22 19:37 ` Andi Kleen
2017-08-22 21:08 ` Christopher Lameter
2017-08-22 21:08 ` Christopher Lameter
2017-08-22 21:24 ` Andi Kleen
2017-08-22 21:24 ` Andi Kleen
2017-08-22 22:52 ` Linus Torvalds
2017-08-22 23:19 ` Linus Torvalds
2017-08-22 23:19 ` Linus Torvalds
2017-08-23 14:51 ` Liang, Kan
2017-08-23 14:51 ` Liang, Kan
2017-08-22 19:55 ` Liang, Kan
2017-08-22 20:42 ` Linus Torvalds
2017-08-22 20:53 ` Peter Zijlstra
2017-08-22 20:53 ` Peter Zijlstra
2017-08-22 20:58 ` Linus Torvalds
2017-08-22 20:58 ` Linus Torvalds
2017-08-23 14:49 ` Liang, Kan
2017-08-23 15:58 ` Tim Chen
2017-08-23 15:58 ` Tim Chen
2017-08-23 18:17 ` Linus Torvalds
2017-08-23 18:17 ` Linus Torvalds
2017-08-23 20:55 ` Liang, Kan
2017-08-23 20:55 ` Liang, Kan
2017-08-23 23:30 ` Linus Torvalds
2017-08-24 17:49 ` Tim Chen
2017-08-24 17:49 ` Tim Chen
2017-08-24 18:16 ` Linus Torvalds
2017-08-24 18:16 ` Linus Torvalds
2017-08-24 20:44 ` Mel Gorman
2017-08-24 20:44 ` Mel Gorman
2017-08-25 16:44 ` Tim Chen
2017-08-25 16:44 ` Tim Chen
2017-08-23 16:04 ` Mel Gorman
2017-08-23 16:04 ` Mel Gorman
2017-08-18 20:05 ` Andi Kleen
2017-08-18 20:05 ` Andi Kleen
2017-08-18 20:29 ` Linus Torvalds
2017-08-18 20:29 ` Linus Torvalds
2017-08-18 20:29 ` Liang, Kan
2017-08-18 20:29 ` Liang, Kan
2017-08-18 20:34 ` Linus Torvalds
2017-08-18 20:34 ` Linus Torvalds
2017-08-18 16:55 ` Linus Torvalds
2017-08-18 16:55 ` Linus Torvalds
2017-08-18 13:06 ` Liang, Kan
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