From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: kosaki.motohiro@jp.fujitsu.com, Mike Waychison <mikew@google.com>,
Nick Piggin <npiggin@suse.de>, Ying Han <yinghan@google.com>,
Ingo Molnar <mingo@elte.hu>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>,
Rohit Seth <rohitseth@google.com>,
Hugh Dickins <hugh@veritas.com>, "H. Peter Anvin" <hpa@zytor.com>,
edwintorok@gmail.com
Subject: Re: [RFC v1][PATCH]page_fault retry with NOPAGE_RETRY
Date: Thu, 27 Nov 2008 20:08:29 +0900 (JST) [thread overview]
Message-ID: <20081127200501.3CF9.KOSAKI.MOTOHIRO@jp.fujitsu.com> (raw)
In-Reply-To: <1227780007.4454.1344.camel@twins>
> Furthermore, /proc code usually isn't written with performance in mind,
> so its usually simple and robust code. Adding it to a 'hot'-path like
> you're doing doesn't seem advisable.
>
> Also, releasing and re-acquiring mmap_sem can significantly add to the
> cacheline bouncing that thing already has.
Interesting.
I tryed to demonstration /proc slowness.
1. make many process
$ nice ./hackbench 120 process 10000
2. read /proc
$ time ps -ef
0.16s user 0.57s system 1% cpu 46.859 total
HAHAHA!
That is really slow over my expected.
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next prev parent reply other threads:[~2008-11-27 11:08 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-22 6:47 Ying Han
2008-11-22 7:15 ` Andrew Morton
2008-11-23 9:18 ` Ingo Molnar
2008-11-23 18:24 ` Andrew Morton
2008-11-25 18:42 ` Ying Han
2008-11-26 12:32 ` Nick Piggin
2008-11-26 19:57 ` Mike Waychison
2008-11-27 8:55 ` Nick Piggin
2008-11-27 9:28 ` Mike Waychison
2008-11-27 10:00 ` Peter Zijlstra
2008-11-27 10:14 ` Nick Piggin
2008-11-27 19:22 ` Mike Waychison
2008-11-28 9:41 ` Nick Piggin
2008-11-28 22:46 ` Mike Waychison
2008-11-27 11:08 ` KOSAKI Motohiro [this message]
2008-11-27 19:10 ` Mike Waychison
2008-11-27 11:39 ` Török Edwin
2008-11-27 12:03 ` Nick Piggin
2008-11-27 12:21 ` Török Edwin
2008-11-27 12:32 ` Peter Zijlstra
2008-11-27 12:39 ` Nick Piggin
2008-11-27 12:52 ` Török Edwin
2008-11-27 13:05 ` Nick Piggin
2008-11-27 13:10 ` Török Edwin
2008-11-27 13:12 ` Nick Piggin
2008-11-27 13:23 ` Török Edwin
2008-11-28 12:10 ` Nick Piggin
2008-11-30 19:38 ` Török Edwin
2008-12-01 8:52 ` Nick Piggin
2008-12-01 11:13 ` Nick Piggin
2008-12-01 11:37 ` Török Edwin
2008-12-04 22:27 ` Ying Han
2008-12-05 6:50 ` Török Edwin
2008-11-27 13:08 ` Nick Piggin
2008-11-27 19:03 ` Mike Waychison
2008-11-28 9:37 ` Nick Piggin
2008-11-28 23:02 ` Mike Waychison
2008-11-30 19:54 ` Török Edwin
2008-12-01 4:50 ` Mike Waychison
2008-12-01 8:58 ` Nick Piggin
2008-12-01 11:45 ` Nick Piggin
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