From: Mel Gorman <mgorman@suse.de>
To: Ingo Molnar <mingo@kernel.org>
Cc: Rik van Riel <riel@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
David Rientjes <rientjes@google.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Paul Turner <pjt@google.com>,
Lee Schermerhorn <Lee.Schermerhorn@hp.com>,
Christoph Lameter <cl@linux.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Johannes Weiner <hannes@cmpxchg.org>,
Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH, v2] mm, numa: Turn 4K pte NUMA faults into effective hugepage ones
Date: Wed, 21 Nov 2012 12:08:58 +0000 [thread overview]
Message-ID: <20121121120857.GB8218@suse.de> (raw)
In-Reply-To: <20121120165239.GA18345@gmail.com>
On Tue, Nov 20, 2012 at 05:52:39PM +0100, Ingo Molnar wrote:
>
> * Rik van Riel <riel@redhat.com> wrote:
>
> > Performance measurements will show us how much of an impact it
> > makes, since I don't think we have never done apples to apples
> > comparisons with just this thing toggled :)
>
> I've done a couple of quick measurements to characterise it: as
> expected this patch simply does not matter much when THP is
> enabled - and most testers I worked with had THP enabled.
>
> Testing with THP off hurst most NUMA workloads dearly and tells
> very little about the real NUMA story of these workloads. If you
> turn off THP you are living with a constant ~25% regression -
> just check the THP and no-THP numbers I posted:
>
> [ 32-warehouse SPECjbb test benchmarks ]
>
> mainline: 395 k/sec
> mainline +THP: 524 k/sec
>
> numa/core +patch: 512 k/sec [ +29.6% ]
> numa/core +patch +THP: 654 k/sec [ +24.8% ]
>
> The group of testers who had THP disabled was thus very low -
> maybe only Mel alone? The testers I worked with all had THP
> enabled.
>
> I'd encourage everyone to report unusual 'tweaks' done before
> tests are reported - no matter how well intended the purpose of
> that tweak.
Jeez, it was an oversight. Do I need to send a card or something?
> There's just so many config variations we can test
> and we obviously check the most logically and most scalably
> configured system variants first.
>
I managed to not break the !THP case for the most part in balancenuma
for the cases I looked at. As stated elsewhere not all machines can
support THP that care about HPC -- ppc64 is a major example. THPs are
not always available, particularly on the node you are trying to migrate
to is fragmented. You can just fail the migration in this case of course
but unless you are willing to compact, this situation can persist for a
long time. You get to keep THP but on a remote node. If we are to ever
choose to split THP to get better placement then we must be able to cope
with the !THP case from the start. Lastly, not all workloads can use THP
if they depend heavily on large files or shared memory.
Focusing on the THP case initially will produce better figures but I worry
it will eventually kick us in the shins and be hard to back out of.
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2012-11-21 12:09 UTC|newest]
Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-19 2:14 [PATCH 00/27] Latest numa/core release, v16 Ingo Molnar
2012-11-19 2:14 ` [PATCH 01/27] mm/generic: Only flush the local TLB in ptep_set_access_flags() Ingo Molnar
2012-11-19 2:14 ` [PATCH 02/27] x86/mm: Only do a local tlb flush " Ingo Molnar
2012-11-19 2:14 ` [PATCH 03/27] x86/mm: Introduce pte_accessible() Ingo Molnar
2012-11-19 2:14 ` [PATCH 04/27] mm: Only flush the TLB when clearing an accessible pte Ingo Molnar
2012-11-19 2:14 ` [PATCH 05/27] x86/mm: Completely drop the TLB flush from ptep_set_access_flags() Ingo Molnar
2012-11-19 2:14 ` [PATCH 06/27] mm: Count the number of pages affected in change_protection() Ingo Molnar
2012-11-19 2:14 ` [PATCH 07/27] mm: Optimize the TLB flush of sys_mprotect() and change_protection() users Ingo Molnar
2012-11-19 2:14 ` [PATCH 08/27] sched, numa, mm: Add last_cpu to page flags Ingo Molnar
2012-11-19 2:14 ` [PATCH 09/27] sched, mm, numa: Create generic NUMA fault infrastructure, with architectures overrides Ingo Molnar
2012-11-19 2:14 ` [PATCH 10/27] sched: Make find_busiest_queue() a method Ingo Molnar
2012-11-19 2:14 ` [PATCH 11/27] sched, numa, mm: Describe the NUMA scheduling problem formally Ingo Molnar
2012-11-19 2:14 ` [PATCH 12/27] numa, mm: Support NUMA hinting page faults from gup/gup_fast Ingo Molnar
2012-11-19 2:14 ` [PATCH 13/27] mm/migrate: Introduce migrate_misplaced_page() Ingo Molnar
2012-11-19 2:14 ` [PATCH 14/27] sched, numa, mm, arch: Add variable locality exception Ingo Molnar
2012-11-19 2:14 ` [PATCH 15/27] sched, numa, mm: Add credits for NUMA placement Ingo Molnar
2012-11-19 2:14 ` [PATCH 16/27] sched, mm, x86: Add the ARCH_SUPPORTS_NUMA_BALANCING flag Ingo Molnar
2012-11-19 2:14 ` [PATCH 17/27] sched, numa, mm: Add the scanning page fault machinery Ingo Molnar
2012-11-19 2:14 ` [PATCH 18/27] sched: Add adaptive NUMA affinity support Ingo Molnar
2012-11-19 2:14 ` [PATCH 19/27] sched: Implement constant, per task Working Set Sampling (WSS) rate Ingo Molnar
2012-11-19 2:14 ` [PATCH 20/27] sched, numa, mm: Count WS scanning against present PTEs, not virtual memory ranges Ingo Molnar
2012-11-19 2:14 ` [PATCH 21/27] sched: Implement slow start for working set sampling Ingo Molnar
2012-11-19 2:14 ` [PATCH 22/27] sched, numa, mm: Interleave shared tasks Ingo Molnar
2012-11-19 2:14 ` [PATCH 23/27] sched: Implement NUMA scanning backoff Ingo Molnar
2012-11-19 2:14 ` [PATCH 24/27] sched: Improve convergence Ingo Molnar
2012-11-19 2:14 ` [PATCH 25/27] sched: Introduce staged average NUMA faults Ingo Molnar
2012-11-19 2:14 ` [PATCH 26/27] sched: Track groups of shared tasks Ingo Molnar
2012-11-19 2:14 ` [PATCH 27/27] sched: Use the best-buddy 'ideal cpu' in balancing decisions Ingo Molnar
2012-11-19 16:29 ` [PATCH 00/27] Latest numa/core release, v16 Mel Gorman
2012-11-19 19:13 ` Ingo Molnar
2012-11-19 21:18 ` Mel Gorman
2012-11-19 22:36 ` Ingo Molnar
2012-11-19 23:00 ` Mel Gorman
2012-11-20 0:41 ` Rik van Riel
2012-11-21 10:58 ` Mel Gorman
2012-11-20 1:02 ` Linus Torvalds
2012-11-20 7:17 ` Ingo Molnar
2012-11-20 7:37 ` David Rientjes
2012-11-20 7:48 ` Ingo Molnar
2012-11-20 8:01 ` Ingo Molnar
2012-11-20 8:11 ` David Rientjes
2012-11-21 11:14 ` Mel Gorman
2012-11-20 10:20 ` Mel Gorman
2012-11-20 10:47 ` Mel Gorman
2012-11-20 15:29 ` [PATCH] mm, numa: Turn 4K pte NUMA faults into effective hugepage ones Ingo Molnar
2012-11-20 16:09 ` [PATCH, v2] " Ingo Molnar
2012-11-20 16:31 ` Rik van Riel
2012-11-20 16:52 ` Ingo Molnar
2012-11-21 12:08 ` Mel Gorman [this message]
2012-11-21 8:12 ` Ingo Molnar
2012-11-21 2:41 ` David Rientjes
2012-11-21 9:34 ` Ingo Molnar
2012-11-21 11:40 ` Mel Gorman
2012-11-23 1:26 ` Alex Shi
2012-11-20 17:56 ` numa/core regressions fixed - more testers wanted Ingo Molnar
2012-11-21 1:54 ` Andrew Theurer
2012-11-21 3:22 ` Rik van Riel
2012-11-21 4:10 ` Hugh Dickins
2012-11-21 17:59 ` Andrew Theurer
2012-11-21 11:52 ` Mel Gorman
2012-11-21 22:15 ` Andrew Theurer
2012-11-21 3:33 ` David Rientjes
2012-11-21 9:38 ` Ingo Molnar
2012-11-21 11:06 ` Ingo Molnar
2012-11-21 8:39 ` Alex Shi
2012-11-22 1:21 ` Ingo Molnar
2012-11-23 13:31 ` Ingo Molnar
2012-11-23 15:23 ` Alex Shi
2012-11-26 2:11 ` Alex Shi
2012-11-28 14:21 ` Alex Shi
2012-11-20 10:40 ` [PATCH 00/27] Latest numa/core release, v16 Ingo Molnar
2012-11-20 11:40 ` Mel Gorman
2012-11-21 10:38 ` Mel Gorman
2012-11-21 19:37 ` Andrea Arcangeli
2012-11-21 19:56 ` Mel Gorman
2012-11-19 20:07 ` Ingo Molnar
2012-11-19 21:37 ` Mel Gorman
2012-11-20 0:50 ` David Rientjes
2012-11-20 1:05 ` David Rientjes
2012-11-20 6:00 ` Ingo Molnar
2012-11-20 6:20 ` David Rientjes
2012-11-20 7:44 ` Ingo Molnar
2012-11-20 7:48 ` Paul Turner
2012-11-20 8:20 ` David Rientjes
2012-11-20 9:06 ` Ingo Molnar
2012-11-20 9:41 ` [patch] x86/vsyscall: Add Kconfig option to use native vsyscalls, switch to it Ingo Molnar
2012-11-20 23:01 ` Andy Lutomirski
2012-11-21 0:43 ` David Rientjes
2012-11-20 12:02 ` [PATCH] x86/mm: Don't flush the TLB on #WP pmd fixups Ingo Molnar
2012-11-20 12:31 ` Ingo Molnar
2012-11-21 11:47 ` Mel Gorman
2012-11-21 1:22 ` David Rientjes
2012-11-21 17:02 ` [PATCH 00/27] Latest numa/core release, v16 Linus Torvalds
2012-11-21 17:10 ` Ingo Molnar
2012-11-21 17:20 ` Ingo Molnar
2012-11-22 4:31 ` David Rientjes
2012-11-21 17:40 ` Ingo Molnar
2012-11-21 22:04 ` Linus Torvalds
2012-11-21 22:46 ` Ingo Molnar
2012-11-21 17:45 ` Rik van Riel
2012-11-21 18:04 ` Ingo Molnar
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