From: Pavel Machek <pavel@ucw.cz>
To: Rogier Wolff <R.E.Wolff@BitWizard.nl>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Sync semantics.
Date: Tue, 16 Nov 2010 15:31:49 +0100 [thread overview]
Message-ID: <20101116143149.GC6527@ucw.cz> (raw)
In-Reply-To: <20101111125219.GA945@bitwizard.nl>
Hi!
> What should I expect from a "sync" system call?
>
> The manual says:
>
> sync() first commits inodes to buffers, and then buffers to disk.
>
> and then goes on to state:
>
> ... since version 1.3.20 Linux does actually wait.
>
> [for the buffers to be handed over to the drive]
>
> So how long can I expect a "sync" call to take?
>
> I would expect that all buffers that are dirty at the time of the
> "sync" call are written by the time that sync returns. I'm currently
> bombarding my fileserver with some 40-60Mbytes per second of data to
> be written (*). The fileserver has 8G of memory. So max 8000 Mb of
Are you sure? Hitting 40MB/sec is hard when it involves seeking...
You may want to lower dirty_ratio...
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2010-11-16 14:32 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-11 12:52 Sync semantics Rogier Wolff
2010-11-12 7:11 ` Michal Svoboda
2010-11-15 2:39 ` Dave Chinner
2010-11-15 7:42 ` Michal Svoboda
2010-11-16 1:16 ` Dave Chinner
2010-11-16 14:31 ` Pavel Machek [this message]
2010-11-17 8:09 ` Rogier Wolff
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