From: Dave Hansen <dave@sr71.net>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>, Hugh Dickins <hughd@google.com>,
Tejun Heo <tj@kernel.org>,
Vladimir Davydov <vdavydov@parallels.com>,
Linus Torvalds <torvalds@linuxfoundation.org>,
Andrew Morton <akpm@linuxfoundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: regression caused by cgroups optimization in 3.17-rc2
Date: Thu, 04 Sep 2014 13:50:34 -0700 [thread overview]
Message-ID: <5408D09A.5030000@sr71.net> (raw)
In-Reply-To: <20140904150846.GA10794@cmpxchg.org>
On 09/04/2014 08:08 AM, Johannes Weiner wrote:
> Dave Hansen reports a massive scalability regression in an uncontained
> page fault benchmark with more than 30 concurrent threads, which he
> bisected down to 05b843012335 ("mm: memcontrol: use root_mem_cgroup
> res_counter") and pin-pointed on res_counter spinlock contention.
>
> That change relied on the per-cpu charge caches to mostly swallow the
> res_counter costs, but it's apparent that the caches don't scale yet.
>
> Revert memcg back to bypassing res_counters on the root level in order
> to restore performance for uncontained workloads.
A quick sniff test shows performance coming back to what it was around
3.16 with this patch. I'll run a more thorough set of tests and verify
that it's working well.
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WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave@sr71.net>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>, Hugh Dickins <hughd@google.com>,
Tejun Heo <tj@kernel.org>,
Vladimir Davydov <vdavydov@parallels.com>,
Linus Torvalds <torvalds@linuxfoundation.org>,
Andrew Morton <akpm@linuxfoundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: regression caused by cgroups optimization in 3.17-rc2
Date: Thu, 04 Sep 2014 13:50:34 -0700 [thread overview]
Message-ID: <5408D09A.5030000@sr71.net> (raw)
In-Reply-To: <20140904150846.GA10794@cmpxchg.org>
On 09/04/2014 08:08 AM, Johannes Weiner wrote:
> Dave Hansen reports a massive scalability regression in an uncontained
> page fault benchmark with more than 30 concurrent threads, which he
> bisected down to 05b843012335 ("mm: memcontrol: use root_mem_cgroup
> res_counter") and pin-pointed on res_counter spinlock contention.
>
> That change relied on the per-cpu charge caches to mostly swallow the
> res_counter costs, but it's apparent that the caches don't scale yet.
>
> Revert memcg back to bypassing res_counters on the root level in order
> to restore performance for uncontained workloads.
A quick sniff test shows performance coming back to what it was around
3.16 with this patch. I'll run a more thorough set of tests and verify
that it's working well.
next prev parent reply other threads:[~2014-09-04 20:50 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-02 19:05 regression caused by cgroups optimization in 3.17-rc2 Dave Hansen
2014-09-02 19:05 ` Dave Hansen
2014-09-02 20:18 ` Dave Hansen
2014-09-02 20:57 ` Dave Hansen
2014-09-02 20:57 ` Dave Hansen
2014-09-04 14:27 ` Michal Hocko
2014-09-04 14:27 ` Michal Hocko
2014-09-04 20:27 ` Dave Hansen
2014-09-04 20:27 ` Dave Hansen
2014-09-04 22:53 ` Dave Hansen
2014-09-04 22:53 ` Dave Hansen
2014-09-05 9:28 ` Michal Hocko
2014-09-05 9:28 ` Michal Hocko
2014-09-05 9:25 ` Michal Hocko
2014-09-05 9:25 ` Michal Hocko
2014-09-05 14:47 ` Johannes Weiner
2014-09-05 14:47 ` Johannes Weiner
2014-09-05 15:39 ` Michal Hocko
2014-09-05 15:39 ` Michal Hocko
2014-09-10 16:29 ` Michal Hocko
2014-09-10 16:29 ` Michal Hocko
2014-09-10 16:57 ` Dave Hansen
2014-09-10 16:57 ` Dave Hansen
2014-09-10 17:05 ` Michal Hocko
2014-09-10 17:05 ` Michal Hocko
2014-09-05 12:35 ` Johannes Weiner
2014-09-05 12:35 ` Johannes Weiner
2014-09-08 15:47 ` Dave Hansen
2014-09-08 15:47 ` Dave Hansen
2014-09-09 14:50 ` Johannes Weiner
2014-09-09 14:50 ` Johannes Weiner
2014-09-09 18:23 ` Dave Hansen
2014-09-09 18:23 ` Dave Hansen
2014-09-02 22:18 ` Johannes Weiner
2014-09-02 22:18 ` Johannes Weiner
2014-09-02 22:36 ` Dave Hansen
2014-09-03 0:10 ` Johannes Weiner
2014-09-03 0:10 ` Johannes Weiner
2014-09-03 0:20 ` Linus Torvalds
2014-09-03 0:20 ` Linus Torvalds
2014-09-03 1:33 ` Johannes Weiner
2014-09-03 1:33 ` Johannes Weiner
2014-09-03 3:15 ` Dave Hansen
2014-09-03 3:15 ` Dave Hansen
2014-09-03 0:30 ` Dave Hansen
2014-09-03 0:30 ` Dave Hansen
2014-09-04 15:08 ` Johannes Weiner
2014-09-04 15:08 ` Johannes Weiner
2014-09-04 20:50 ` Dave Hansen [this message]
2014-09-04 20:50 ` Dave Hansen
2014-09-05 8:04 ` Michal Hocko
2014-09-05 8:04 ` Michal Hocko
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