From: Mel Gorman <mel@csn.ul.ie>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <pzijlstr@redhat.com>, Ingo Molnar <mingo@elte.hu>,
Hugh Dickins <hughd@google.com>, Rik van Riel <riel@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Hillf Danton <dhillf@gmail.com>,
Andrew Jones <drjones@redhat.com>, Dan Smith <danms@us.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Paul Turner <pjt@google.com>, Christoph Lameter <cl@linux.com>,
Suresh Siddha <suresh.b.siddha@intel.com>,
Mike Galbraith <efault@gmx.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
Bharata B Rao <bharata.rao@gmail.com>,
Lee Schermerhorn <Lee.Schermerhorn@hp.com>,
Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
Alex Shi <alex.shi@intel.com>,
Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Don Morris <don.morris@hp.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [PATCH 00/33] AutoNUMA27
Date: Thu, 11 Oct 2012 22:34:32 +0100 [thread overview]
Message-ID: <20121011213432.GQ3317@csn.ul.ie> (raw)
In-Reply-To: <1349308275-2174-1-git-send-email-aarcange@redhat.com>
On Thu, Oct 04, 2012 at 01:50:42AM +0200, Andrea Arcangeli wrote:
> Hello everyone,
>
> This is a new AutoNUMA27 release for Linux v3.6.
>
So after getting through the full review of it, there wasn't anything
I could not stand. I think it's *very* heavy on some of the paths like
the idle balancer which I was not keen on and the fault paths are also
quite heavy. I think the weight on some of these paths can be reduced
but not to 0 if the objectives to autonuma are to be met.
I'm not fully convinced that the task exchange is actually necessary or
beneficial because it somewhat assumes that there is a symmetry between CPU
and memory balancing that may not be true. The fact that it only considers
tasks that are currently running feels a bit random but examining all tasks
that recently ran on the node would be far too expensive to there is no
good answer. You are caught between a rock and a hard place and either
direction you go is wrong for different reasons. You need something more
frequent than scans (because it'll converge too slowly) but doing it from
the balancer misses some tasks and may run too frequently and it's unclear
how it effects the current load balancer decisions. I don't have a good
alternative solution for this but ideally it would be better integrated with
the existing scheduler when there is more data on what those scheduling
decisions should be. That will only come from a wide range of testing and
the inevitable bug reports.
That said, this is concentrating on the problems without considering the
situations where it would work very well. I think it'll come down to HPC
and anything jitter-sensitive will hate this while workloads like JVM,
virtualisation or anything that uses a lot of memory without caring about
placement will love it. It's not perfect but it's better than incurring
the cost of remote access unconditionally.
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2012-10-11 21:34 UTC|newest]
Thread overview: 114+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-03 23:50 Andrea Arcangeli
2012-10-03 23:50 ` [PATCH 01/33] autonuma: add Documentation/vm/autonuma.txt Andrea Arcangeli
2012-10-11 10:50 ` Mel Gorman
2012-10-11 16:07 ` Andrea Arcangeli
2012-10-11 19:37 ` Mel Gorman
2012-10-03 23:50 ` [PATCH 02/33] autonuma: make set_pmd_at always available Andrea Arcangeli
2012-10-11 10:54 ` Mel Gorman
2012-10-03 23:50 ` [PATCH 03/33] autonuma: export is_vma_temporary_stack() even if CONFIG_TRANSPARENT_HUGEPAGE=n Andrea Arcangeli
2012-10-11 10:54 ` Mel Gorman
2012-10-03 23:50 ` [PATCH 04/33] autonuma: define _PAGE_NUMA Andrea Arcangeli
2012-10-11 11:01 ` Mel Gorman
2012-10-11 16:43 ` Andrea Arcangeli
2012-10-11 19:48 ` Mel Gorman
2012-10-03 23:50 ` [PATCH 05/33] autonuma: pte_numa() and pmd_numa() Andrea Arcangeli
2012-10-11 11:15 ` Mel Gorman
2012-10-11 16:58 ` Andrea Arcangeli
2012-10-11 19:54 ` Mel Gorman
2012-10-03 23:50 ` [PATCH 06/33] autonuma: teach gup_fast about pmd_numa Andrea Arcangeli
2012-10-11 12:22 ` Mel Gorman
2012-10-11 17:05 ` Andrea Arcangeli
2012-10-11 20:01 ` Mel Gorman
2012-10-03 23:50 ` [PATCH 07/33] autonuma: mm_autonuma and task_autonuma data structures Andrea Arcangeli
2012-10-11 12:28 ` Mel Gorman
2012-10-11 15:24 ` Rik van Riel
2012-10-11 15:57 ` Mel Gorman
2012-10-12 0:23 ` Christoph Lameter
2012-10-12 0:52 ` Andrea Arcangeli
2012-10-11 17:15 ` Andrea Arcangeli
2012-10-11 20:06 ` Mel Gorman
2012-10-03 23:50 ` [PATCH 08/33] autonuma: define the autonuma flags Andrea Arcangeli
2012-10-11 13:46 ` Mel Gorman
2012-10-11 17:34 ` Andrea Arcangeli
2012-10-11 20:17 ` Mel Gorman
2012-10-03 23:50 ` [PATCH 09/33] autonuma: core autonuma.h header Andrea Arcangeli
2012-10-03 23:50 ` [PATCH 10/33] autonuma: CPU follows memory algorithm Andrea Arcangeli
2012-10-11 14:58 ` Mel Gorman
2012-10-12 0:25 ` Andrea Arcangeli
2012-10-12 8:29 ` Mel Gorman
2012-10-03 23:50 ` [PATCH 11/33] autonuma: add the autonuma_last_nid in the page structure Andrea Arcangeli
2012-10-03 23:50 ` [PATCH 12/33] autonuma: Migrate On Fault per NUMA node data Andrea Arcangeli
2012-10-11 15:43 ` Mel Gorman
2012-10-03 23:50 ` [PATCH 13/33] autonuma: autonuma_enter/exit Andrea Arcangeli
2012-10-11 13:50 ` Mel Gorman
2012-10-03 23:50 ` [PATCH 14/33] autonuma: call autonuma_setup_new_exec() Andrea Arcangeli
2012-10-11 15:47 ` Mel Gorman
2012-10-03 23:50 ` [PATCH 15/33] autonuma: alloc/free/init task_autonuma Andrea Arcangeli
2012-10-11 15:53 ` Mel Gorman
2012-10-11 17:34 ` Rik van Riel
[not found] ` <20121011175953.GT1818@redhat.com>
2012-10-12 14:03 ` Rik van Riel
2012-10-03 23:50 ` [PATCH 16/33] autonuma: alloc/free/init mm_autonuma Andrea Arcangeli
2012-10-03 23:50 ` [PATCH 17/33] autonuma: prevent select_task_rq_fair to return -1 Andrea Arcangeli
2012-10-03 23:51 ` [PATCH 18/33] autonuma: teach CFS about autonuma affinity Andrea Arcangeli
2012-10-05 6:41 ` Mike Galbraith
2012-10-05 11:54 ` Andrea Arcangeli
2012-10-06 2:39 ` Mike Galbraith
2012-10-06 12:34 ` Andrea Arcangeli
2012-10-07 6:07 ` Mike Galbraith
2012-10-08 7:03 ` Mike Galbraith
2012-10-03 23:51 ` [PATCH 19/33] autonuma: memory follows CPU algorithm and task/mm_autonuma stats collection Andrea Arcangeli
2012-10-10 22:01 ` Rik van Riel
2012-10-10 22:36 ` Andrea Arcangeli
2012-10-11 18:28 ` Mel Gorman
2012-10-13 18:06 ` Srikar Dronamraju
2012-10-15 8:24 ` Srikar Dronamraju
2012-10-15 9:20 ` Mel Gorman
2012-10-15 10:00 ` Srikar Dronamraju
2012-10-03 23:51 ` [PATCH 20/33] autonuma: default mempolicy follow AutoNUMA Andrea Arcangeli
2012-10-04 20:03 ` KOSAKI Motohiro
2012-10-11 18:32 ` Mel Gorman
2012-10-03 23:51 ` [PATCH 21/33] autonuma: call autonuma_split_huge_page() Andrea Arcangeli
2012-10-11 18:33 ` Mel Gorman
2012-10-03 23:51 ` [PATCH 22/33] autonuma: make khugepaged pte_numa aware Andrea Arcangeli
2012-10-11 18:36 ` Mel Gorman
2012-10-03 23:51 ` [PATCH 23/33] autonuma: retain page last_nid information in khugepaged Andrea Arcangeli
2012-10-11 18:44 ` Mel Gorman
2012-10-12 11:37 ` Rik van Riel
2012-10-12 12:35 ` Mel Gorman
2012-10-03 23:51 ` [PATCH 24/33] autonuma: split_huge_page: transfer the NUMA type from the pmd to the pte Andrea Arcangeli
2012-10-11 18:45 ` Mel Gorman
2012-10-03 23:51 ` [PATCH 25/33] autonuma: numa hinting page faults entry points Andrea Arcangeli
2012-10-11 18:47 ` Mel Gorman
2012-10-03 23:51 ` [PATCH 26/33] autonuma: reset autonuma page data when pages are freed Andrea Arcangeli
2012-10-03 23:51 ` [PATCH 27/33] autonuma: link mm/autonuma.o and kernel/sched/numa.o Andrea Arcangeli
2012-10-03 23:51 ` [PATCH 28/33] autonuma: add CONFIG_AUTONUMA and CONFIG_AUTONUMA_DEFAULT_ENABLED Andrea Arcangeli
2012-10-11 18:50 ` Mel Gorman
2012-10-03 23:51 ` [PATCH 29/33] autonuma: page_autonuma Andrea Arcangeli
2012-10-04 14:16 ` Christoph Lameter
2012-10-04 20:09 ` KOSAKI Motohiro
2012-10-05 11:31 ` Andrea Arcangeli
2012-10-03 23:51 ` [PATCH 30/33] autonuma: bugcheck page_autonuma fields on newly allocated pages Andrea Arcangeli
2012-10-03 23:51 ` [PATCH 31/33] autonuma: boost khugepaged scanning rate Andrea Arcangeli
2012-10-03 23:51 ` [PATCH 32/33] autonuma: add migrate_allow_first_fault knob in sysfs Andrea Arcangeli
2012-10-03 23:51 ` [PATCH 33/33] autonuma: add mm_autonuma working set estimation Andrea Arcangeli
2012-10-04 18:39 ` [PATCH 00/33] AutoNUMA27 Andrew Morton
2012-10-04 20:49 ` Rik van Riel
2012-10-05 23:08 ` Rik van Riel
2012-10-05 23:14 ` Andi Kleen
2012-10-05 23:57 ` Tim Chen
2012-10-06 0:11 ` Andi Kleen
2012-10-08 13:44 ` Don Morris
2012-10-08 20:34 ` Rik van Riel
2012-10-11 10:19 ` Mel Gorman
2012-10-11 14:56 ` Andrea Arcangeli
2012-10-11 15:35 ` Mel Gorman
2012-10-12 0:41 ` Andrea Arcangeli
2012-10-12 14:54 ` Mel Gorman
2012-10-11 21:34 ` Mel Gorman [this message]
2012-10-12 1:45 ` Andrea Arcangeli
2012-10-12 8:46 ` Mel Gorman
2012-10-13 18:40 ` Srikar Dronamraju
2012-10-14 4:57 ` Andrea Arcangeli
2012-10-15 8:16 ` Srikar Dronamraju
2012-10-23 16:32 ` Srikar Dronamraju
2012-10-16 13:48 ` Mel Gorman
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