From: Andrea Arcangeli <andrea@novell.com>
To: Jesse Barnes <jbarnes@engr.sgi.com>
Cc: William Lee Irwin III <wli@holomorphy.com>,
Andrew Morton <akpm@osdl.org>, Ray Bryant <raybry@sgi.com>,
hawkes@sgi.com, linux-kernel@vger.kernel.org
Subject: Re: [profile] amortize atomic hit count increments
Date: Tue, 14 Sep 2004 18:31:43 +0200 [thread overview]
Message-ID: <20040914163143.GQ4180@dualathlon.random> (raw)
In-Reply-To: <200409140916.48786.jbarnes@engr.sgi.com>
On Tue, Sep 14, 2004 at 09:16:48AM -0700, Jesse Barnes wrote:
> the readprofile times, I'd say per-cpu would be the way to go just because it
> retains the simplicity of the current approach while allowing it to work on
> large machines (as well as limiting the performance impact of builtin
> profiling in general). wli's approach seems like a reasonable tradeoff
> though, assuming what you suggest doesn't work.
per-cpu certainly sounds simple enough conceptually, so if you can
notice any slowdown even with idle loop ruled out, per-cpu is sure
better.
This bouncing is likely to hurt smaller SMP too (but once the cpu is
idle normally it's not a too bad thing since it only hurted reschedule
latency, since we remain stuck in the timer irq for a bit longer than we
should), but duplicating the ram of the array there doesn't look as nice
as it would be on the altix, not all SMP have tons of ram. So an
intermediate solution for this problem still sound worthwhile for the
normal smp case.
next prev parent reply other threads:[~2004-09-14 17:02 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-13 8:50 2.6.9-rc1-mm5 Andrew Morton
2004-09-13 9:22 ` 2.6.9-rc1-mm5 Nick Piggin
2004-09-13 17:24 ` 2.6.9-rc1-mm5 Jesse Barnes
2004-09-13 18:06 ` 2.6.9-rc1-mm5 Paul Jackson
2004-09-13 18:10 ` 2.6.9-rc1-mm5 Jesse Barnes
2004-09-13 21:30 ` 2.6.9-rc1-mm5 Jesse Barnes
2004-09-14 2:02 ` 2.6.9-rc1-mm5 Nick Piggin
2004-09-14 2:12 ` 2.6.9-rc1-mm5 Jesse Barnes
2004-09-13 10:20 ` 2.6.9-rc1-mm5 Christoph Hellwig
2004-09-13 10:48 ` 2.6.9-rc1-mm5 Rafael J. Wysocki
2004-09-13 11:13 ` 2.6.9-rc1-mm5 Nikita Danilov
2004-09-13 13:40 ` 2.6.9-rc1-mm5 Christoph Hellwig
2004-09-13 11:16 ` 2.6.9-rc1-mm5 Rafael J. Wysocki
2004-09-13 11:01 ` 2.6.9-rc1-mm5 William Lee Irwin III
2004-09-13 15:09 ` 2.6.9-rc1-mm5 Martin J. Bligh
2004-09-13 15:18 ` 2.6.9-rc1-mm5 Paul Jackson
2004-09-13 16:11 ` 2.6.9-rc1-mm5 Martin J. Bligh
2004-09-13 16:22 ` 2.6.9-rc1-mm5 Paul Jackson
2004-09-13 15:20 ` 2.6.9-rc1-mm5 Kirill Korotaev
2004-09-13 20:01 ` 2.6.9-rc1-mm5 Andrew Morton
2004-09-14 6:39 ` 2.6.9-rc1-mm5 Kirill Korotaev
2004-09-13 20:30 ` 2.6.9-rc1-mm5 Pasi Savolainen
2004-09-13 21:06 ` 2.6.9-rc1-mm5 Rafael J. Wysocki
2004-09-14 9:07 ` 2.6.9-rc1-mm5 Nikita Danilov
2004-09-14 9:12 ` 2.6.9-rc1-mm5 Andrew Morton
2004-09-14 13:21 ` 2.6.9-rc1-mm5 David Howells
2004-09-14 14:24 ` 2.6.9-rc1-mm5 James Morris
2004-09-14 15:36 ` 2.6.9-rc1-mm5 David Howells
2004-09-13 21:47 ` 2.6.9-rc1-mm5 scheduling while atomic Jesse Barnes
2004-09-13 22:56 ` Paul Jackson
2004-09-13 21:56 ` 2.6.9-rc1-mm5 bug in tcp_recvmsg? Jesse Barnes
2004-09-13 22:36 ` David S. Miller
2004-09-13 22:44 ` Jesse Barnes
2004-09-13 22:47 ` David S. Miller
2004-09-13 23:54 ` Jesse Barnes
2004-09-13 23:55 ` David S. Miller
2004-09-14 0:03 ` Jesse Barnes
2004-09-14 0:21 ` David S. Miller
2004-09-14 17:09 ` Jesse Barnes
2004-09-14 0:25 ` 2.6.9-rc1-mm5: TCP oopses James Morris
2004-09-14 2:08 ` David S. Miller
2004-09-14 3:04 ` James Morris
2004-09-14 3:34 ` Herbert Xu
2004-09-14 4:53 ` David S. Miller
2004-09-14 4:55 ` David S. Miller
2004-09-14 5:07 ` James Morris
2004-09-14 2:25 ` [pidhashing] [0/3] pid allocator updates William Lee Irwin III
2004-09-14 2:28 ` [pidhashing] [1/3] retain older vendor copyright William Lee Irwin III
2004-09-14 2:31 ` [pidhashing] [2/3] lower PID_MAX_LIMIT for 32-bit machines William Lee Irwin III
2004-09-14 2:36 ` [pidhashing] [3/3] enforce PID_MAX_LIMIT in sysctls William Lee Irwin III
2004-09-14 2:38 ` [pidhashing] [2/3] lower PID_MAX_LIMIT for 32-bit machines William Lee Irwin III
2004-09-14 10:55 ` Roger Luethi
2004-09-14 11:10 ` Lars Marowsky-Bree
2004-09-14 12:06 ` Lars Marowsky-Bree
2004-09-14 12:08 ` Roger Luethi
2004-09-14 15:41 ` William Lee Irwin III
2004-09-14 15:47 ` Roger Leuthi
2004-09-14 16:41 ` William Lee Irwin III
2004-09-14 17:16 ` Roger Luethi
2004-09-14 2:53 ` [procfs] [1/1] fix task_mmu.c text size reporting William Lee Irwin III
2004-09-14 2:54 ` William Lee Irwin III
2004-09-15 10:51 ` [procfs] [2/1] report per-process pagetable usage William Lee Irwin III
2004-09-14 4:47 ` [profile] amortize atomic hit count increments William Lee Irwin III
2004-09-14 5:05 ` David S. Miller
2004-09-14 5:32 ` William Lee Irwin III
2004-09-14 5:49 ` David S. Miller
2004-09-14 6:10 ` William Lee Irwin III
2004-09-14 6:18 ` William Lee Irwin III
2004-09-14 5:05 ` Andrew Morton
2004-09-14 5:21 ` William Lee Irwin III
2004-09-14 6:43 ` William Lee Irwin III
2004-09-14 6:52 ` Andrew Morton
2004-09-14 7:55 ` William Lee Irwin III
2004-09-14 8:48 ` William Lee Irwin III
2004-09-14 11:34 ` Andrea Arcangeli
2004-09-14 15:51 ` William Lee Irwin III
2004-09-14 16:05 ` Andrea Arcangeli
2004-09-14 16:16 ` Jesse Barnes
2004-09-14 16:31 ` Andrea Arcangeli [this message]
2004-09-14 16:45 ` William Lee Irwin III
2004-09-14 19:00 ` William Lee Irwin III
2004-09-14 19:23 ` William Lee Irwin III
2004-09-14 20:02 ` William Lee Irwin III
2004-09-14 20:04 ` William Lee Irwin III
2004-09-14 21:04 ` William Lee Irwin III
2004-09-14 21:11 ` William Lee Irwin III
2004-09-14 10:00 ` 2.6.9-rc1-mm5 Lorenzo Allegrucci
2004-09-15 11:36 ` 2.6.9-rc1-mm5 William Lee Irwin III
2004-09-15 11:38 ` 2.6.9-rc1-mm5 Jens Axboe
2004-09-15 12:28 ` 2.6.9-rc1-mm5 William Lee Irwin III
2004-09-15 12:41 ` 2.6.9-rc1-mm5 Jens Axboe
2004-09-15 12:50 ` 2.6.9-rc1-mm5 Jens Axboe
2004-09-15 12:53 ` 2.6.9-rc1-mm5 William Lee Irwin III
2004-09-16 0:38 ` 2.6.9-rc1-mm5 William Lee Irwin III
2004-09-16 5:44 ` 2.6.9-rc1-mm5 William Lee Irwin III
2004-09-16 5:45 ` 2.6.9-rc1-mm5 Jens Axboe
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