From: Pavel Machek <pavel@denx.de>
To: David Laight <David.Laight@ACULAB.COM>
Cc: 'Christophe Leroy' <christophe.leroy@csgroup.eu>,
Christoph Hellwig <hch@lst.de>, "arnd@arndb.de" <arnd@arndb.de>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] /dev/zero: also implement ->read
Date: Sun, 6 Sep 2020 20:21:22 +0200 [thread overview]
Message-ID: <20200906182122.GA12295@amd> (raw)
In-Reply-To: <3b0b58be4b844162b73db1b108a9b995@AcuMS.aculab.com>
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Hi!
> > > 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?
Exactly. Also it would be nice to note how the speedup was measured
and what the speedup is.
Best regads,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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next prev parent reply other threads:[~2020-09-06 18:21 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-03 15:59 [PATCH] /dev/zero: also implement ->read Christoph Hellwig
2020-09-03 16:05 ` Christophe Leroy
2020-09-03 21:35 ` David Laight
2020-09-06 18:21 ` Pavel Machek [this message]
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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