From: Benjamin LaHaise <bcrl@kvack.org>
To: Andrew Morton <akpm@osdl.org>
Cc: john@johnmccutchan.com, holt@sgi.com,
linux-kernel@vger.kernel.org, rml@novell.com, arnd@arndb.de,
hch@lst.de
Subject: Re: udevd is killing file write performance.
Date: Thu, 23 Feb 2006 15:38:26 -0500 [thread overview]
Message-ID: <20060223203826.GC30329@kvack.org> (raw)
In-Reply-To: <20060222151223.5c9061fd.akpm@osdl.org>
On Wed, Feb 22, 2006 at 03:12:23PM -0800, Andrew Morton wrote:
> It's not a terribly bad hack - it's just poor-man's hashing, and it's
> reasonably well-suited to the sorts of machines and workloads which we
> expect will hit this problem.
The dnotify/inotify wakeups are a problem, namely because the implementation
is braindead: it makes the wrong part of the interface fast (setting up
notify entries) at the expense of making the rest of the kernel slow (adding
locks to read()/write()). read() and write() are incredibly hot paths in
the kernel and should be optimized at the expense of dnotify and inotify,
which are uncommon operations.
-ben
--
"Ladies and gentlemen, I'm sorry to interrupt, but the police are here
and they've asked us to stop the party." Don't Email: <dont@kvack.org>.
prev parent reply other threads:[~2006-02-23 20:43 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-22 13:42 udevd is killing file write performance Robin Holt
2006-02-22 13:55 ` Andrew Morton
2006-02-22 16:48 ` John McCutchan
2006-02-22 17:50 ` Robin Holt
2006-02-22 20:05 ` Andrew Morton
2006-02-22 21:50 ` Jeff V. Merkey
2006-02-23 12:56 ` Robin Holt
2006-02-23 13:42 ` David Chinner
2006-02-22 22:52 ` John McCutchan
2006-02-22 23:12 ` Andrew Morton
2006-02-22 23:41 ` John McCutchan
2006-02-24 0:14 ` Andrew Morton
2006-02-24 0:14 ` Andrew Morton
2006-02-24 5:47 ` John McCutchan
2006-02-24 6:00 ` Andrew Morton
2006-02-24 7:07 ` Nick Piggin
2006-02-24 7:16 ` Andrew Morton
2006-02-24 7:19 ` Nick Piggin
2006-02-26 16:58 ` John McCutchan
2006-02-24 18:56 ` Robin Holt
2006-02-25 2:44 ` Nick Piggin
2006-02-25 15:53 ` [patch] inotify: lock avoidance with parent watch status in dentry Nick Piggin
2006-02-28 0:48 ` Andrew Morton
2006-02-26 16:55 ` udevd is killing file write performance John McCutchan
2006-02-27 10:11 ` Nick Piggin
2006-02-27 20:17 ` John McCutchan
2006-02-23 20:38 ` Benjamin LaHaise [this message]
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