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From: David Laight <David.Laight@ACULAB.COM>
To: 'Christophe Leroy' <christophe.leroy@csgroup.eu>,
	Christoph Hellwig <hch@lst.de>, "arnd@arndb.de" <arnd@arndb.de>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] /dev/zero: also implement ->read
Date: Thu, 3 Sep 2020 21:35:00 +0000	[thread overview]
Message-ID: <3b0b58be4b844162b73db1b108a9b995@AcuMS.aculab.com> (raw)
In-Reply-To: <55d1ecb8-4a0c-fa58-d3cf-bf6796eea7bd@csgroup.eu>

From: Christophe Leroy
> 
> 
> Le 03/09/2020 à 17:59, Christoph Hellwig a écrit :
> > Christophe reported a major speedup due to avoiding the iov_iter
> > overhead, so just add this trivial function.  Note that /dev/zero
> > already implements both an iter and non-iter writes so this just
> > makes it more symmetric.
> >
> > Christophe Leroy <christophe.leroy@csgroup.eu>
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> 
> Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu>

Any idea what has happened to make the 'iter' version so bad?

	David

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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

  reply	other threads:[~2020-09-03 21:35 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-03 15:59 Christoph Hellwig
2020-09-03 16:05 ` Christophe Leroy
2020-09-03 21:35   ` David Laight [this message]
2020-09-06 18:21     ` Pavel Machek
2020-09-06 18:35       ` Christophe Leroy
2020-09-06 18:38         ` Pavel Machek
2020-09-06 18:47           ` Christophe Leroy
2020-09-06 20:09           ` gregkh
2020-09-06 20:52         ` David Laight
2020-09-07  4:44           ` Christophe Leroy
2020-09-07  8:18             ` David Laight
2020-09-03 17:51 ` Christophe Leroy
2020-09-03 18:02   ` Greg KH
2020-09-06 22:34 ` Rasmus Villemoes
2020-09-07  6:20   ` Christoph Hellwig
2020-09-07  6:50     ` Rasmus Villemoes
2020-09-07  7:30       ` Christoph Hellwig

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