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From: David Howells <dhowells@redhat.com>
To: Dave Chinner <david@fromorbit.com>
Cc: dhowells@redhat.com, adilger@dilger.ca, bfields@fieldses.org,
	smfrench@gmail.com, ben@decadent.org.uk,
	Trond.Myklebust@netapp.com, roland@hack.frob.com,
	linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org,
	linux-cifs@vger.kernel.org, samba-technical@lists.samba.org,
	linux-ext4@vger.kernel.org, linux-api@vger.kernel.org,
	libc-alpha@sourceware.org
Subject: Re: Extended file stat: Splitting file- and fs-specific info?
Date: Thu, 10 May 2012 10:14:11 +0100	[thread overview]
Message-ID: <13791.1336641251@redhat.com> (raw)
In-Reply-To: <20120509002420.GL5091@dastard>

Dave Chinner <david@fromorbit.com> wrote:

> > Also, do Dave Chinner's ideas for indicating five I/O parameters want to be
> > 32-bit numbers?  Larger?  Smaller?  Can they be log2?
> 
> Definitely 32 bit, IMO, as it's not uncommon to see optimal IO sizes
> in the tens of megabytes on large, high bandwidth storage systems.
> As for being log2 - that's just making it more complex to use and
> making code ugly - we'd have to convert to log2 in kernel, then
> convert back in every single application....

ilog2() in the kernel uses the CPU's bit-scan instruction if it has one and
converting back is just a bitshift operator.

But let's go with 32-bit fields for the moment.  I presume we aren't worried
about a driver that wants to do a 4GB transfer...

David

      parent reply	other threads:[~2012-05-10  9:14 UTC|newest]

Thread overview: 86+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-19 14:05 [PATCH 0/6] Extended file stat system call David Howells
2012-04-19 14:06 ` [PATCH 1/6] xstat: Add a pair of system calls to make extended file stats available David Howells
2012-04-19 23:36   ` Andreas Dilger
2012-04-24 21:29   ` J. Bruce Fields
2012-04-24 22:08     ` Steve French
2012-04-25 14:44     ` Andreas Dilger
2012-04-26 13:45     ` David Howells
2012-04-26 14:28       ` J. Bruce Fields
2012-04-26 17:06         ` Steve French
2012-04-26 13:32   ` David Howells
2012-04-27  0:51     ` Dave Chinner
2012-04-27  3:11       ` Andreas Dilger
2012-04-26 13:40   ` David Howells
2012-04-26 14:23     ` J. Bruce Fields
2012-04-19 14:06 ` [PATCH 2/6] xstat: Ext4: Return extended attributes David Howells
2012-04-19 16:03   ` Steve French
2012-04-26 13:47   ` David Howells
2012-04-26 17:00     ` Steve French
2012-04-19 14:06 ` [PATCH 3/6] xstat: AFS: " David Howells
2012-04-19 14:06 ` [PATCH 4/6] xstat: NFS: " David Howells
2012-04-19 14:35   ` Myklebust, Trond
2012-04-26 13:52   ` David Howells
2012-04-19 14:07 ` [PATCH 5/6] xstat: CIFS: " David Howells
2012-04-19 15:19   ` Steve French
2012-04-19 14:07 ` [PATCH 6/6] xstat: eCryptFS: " David Howells
2012-04-19 16:32 ` [PATCH 0/6] Extended file stat system call Roland McGrath
2012-04-19 21:51   ` Paul Eggert
2012-04-19 23:05     ` Roland McGrath
2012-04-26 14:16     ` David Howells
2012-04-26 18:22       ` Roland McGrath
2012-04-26 14:04   ` David Howells
2012-04-26 18:24     ` Roland McGrath
2012-04-19 17:11 ` Steve French
2012-04-19 23:29 ` Andreas Dilger
2012-04-26 13:54 ` David Howells
2012-04-26 18:25   ` Roland McGrath
2012-04-27 23:54     ` Paul Eggert
2012-04-26 21:54   ` David Howells
2012-04-26 22:02     ` Roland McGrath
2012-04-26 22:21       ` Nix
2012-04-26 14:25 ` David Howells
2012-04-26 14:54   ` Steve French
2012-04-26 15:25     ` Myklebust, Trond
2012-04-26 16:56       ` Steve French
2012-04-26 17:00         ` Myklebust, Trond
2012-04-26 17:03           ` Steve French
2012-04-26 17:06             ` Myklebust, Trond
2012-04-26 17:09               ` Steve French
2012-04-26 17:10                 ` Steve French
2012-04-26 21:57             ` David Howells
2012-04-26 22:05               ` Roland McGrath
2012-04-27  0:33                 ` Myklebust, Trond
2012-04-27  0:30               ` Myklebust, Trond
2012-04-26 15:52   ` David Howells
2012-04-27  0:29     ` Andreas Dilger
2012-04-27  9:19     ` David Howells
2012-04-27  1:06 ` Dave Chinner
2012-04-27  3:22   ` Andreas Dilger
2012-04-28  0:38     ` Dave Chinner
2012-04-28  0:54       ` Steve French
2012-04-27  9:39 ` David Howells
2012-04-27 13:13   ` Dave Chinner
2012-04-27 15:10     ` J. Bruce Fields
2012-04-27 16:32       ` Steve French
2012-04-27 19:31     ` Andreas Dilger
2012-04-28  0:58       ` Dave Chinner
2012-05-10  9:51       ` David Howells
2012-05-08 20:19 ` Extended file stat: Splitting file- and fs-specific info? David Howells
2012-05-08 21:13   ` Myklebust, Trond
2012-05-09  0:24   ` Dave Chinner
2012-05-09  1:09     ` J. Bruce Fields
2012-05-09  4:25       ` Dave Chinner
2012-05-09 11:14         ` J. Bruce Fields
2012-05-09  1:16     ` Andreas Dilger
2012-05-10  9:23     ` David Howells
2012-05-10 16:05       ` Andreas Dilger
2012-05-10 17:10       ` Roland McGrath
2012-05-11  8:54         ` Andreas Dilger
2012-05-09  9:21   ` David Howells
2012-05-09 11:19     ` Christoph Hellwig
2012-05-09 11:55       ` Bernd Schubert
2012-05-09 12:05         ` Christoph Hellwig
2012-05-09 12:25           ` Bernd Schubert
2012-05-09 13:51             ` Andreas Dilger
2012-05-09 14:12               ` Bernd Schubert
2012-05-10  9:14   ` David Howells [this message]

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