From: Linus Torvalds <torvalds@linux-foundation.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Nick Piggin <npiggin@suse.de>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Pierre Tardy <tardyp@gmail.com>, Ingo Molnar <mingo@elte.hu>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Tom Zanussi <tzanussi@gmail.com>,
Paul Mackerras <paulus@samba.org>,
linux-kernel@vger.kernel.org, arjan@infradead.org,
ziga.mahkovec@gmail.com, davem <davem@davemloft.net>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Christoph Lameter <cl@linux-foundation.org>,
Tejun Heo <tj@kernel.org>, Jens Axboe <jens.axboe@oracle.com>
Subject: Re: Unexpected splice "always copy" behavior observed
Date: Wed, 19 May 2010 07:59:48 -0700 (PDT) [thread overview]
Message-ID: <alpine.LFD.2.00.1005190758070.23538@i5.linux-foundation.org> (raw)
In-Reply-To: <1274280968.26328.774.camel@gandalf.stny.rr.com>
On Wed, 19 May 2010, Steven Rostedt wrote:
> On Wed, 2010-05-19 at 07:39 -0700, Linus Torvalds wrote:
>
> > The real limitation is likely always going to be the fact that it has to
> > be page-aligned and a full page. For a lot of splice inputs, that simply
> > won't be the case, and you'll end up copying for alignment reasons anyway.
>
> That's understandable. For the use cases of splice I use, I work to make
> it page aligned and full pages. Anyone else using splice for
> optimizations, should do the same. It only makes sense.
>
> The end of buffer may not be a full page, but then it's the end anyway,
> and I'm not as interested in the speed.
Btw, since you apparently have a real case - is the "splice to file"
always just an append? IOW, if I'm not right in assuming that the only
sane thing people would reasonable care about is "append to a file", then
holler now.
Linus
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next prev parent reply other threads:[~2010-05-19 15:02 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-18 15:34 Mathieu Desnoyers
2010-05-18 15:51 ` Nick Piggin
2010-05-18 15:56 ` Christoph Lameter
2010-05-18 16:00 ` Nick Piggin
2010-05-18 16:13 ` Nick Piggin
2010-05-18 15:53 ` Steven Rostedt
2010-05-18 16:10 ` Steven Rostedt
2010-05-18 16:25 ` Linus Torvalds
2010-05-19 6:31 ` Nick Piggin
2010-05-19 14:39 ` Linus Torvalds
2010-05-19 14:56 ` Steven Rostedt
2010-05-19 14:59 ` Linus Torvalds [this message]
2010-05-19 15:12 ` Steven Rostedt
2010-05-19 15:51 ` Mathieu Desnoyers
2010-05-19 15:33 ` Miklos Szeredi
2010-05-19 15:45 ` Steven Rostedt
2010-05-19 15:55 ` Nick Piggin
2010-05-19 16:01 ` Mathieu Desnoyers
2010-05-19 16:36 ` Steven Rostedt
2010-05-19 15:57 ` Mathieu Desnoyers
2010-05-19 16:27 ` Nick Piggin
2010-05-19 19:14 ` Mathieu Desnoyers
2010-05-19 19:31 ` Linus Torvalds
2010-05-19 21:49 ` Mathieu Desnoyers
2010-05-20 0:04 ` Linus Torvalds
2010-05-20 1:56 ` Mathieu Desnoyers
2010-05-20 14:18 ` Linus Torvalds
2010-05-19 20:59 ` Rick Sherm
2010-05-19 15:17 ` Nick Piggin
2010-05-19 15:30 ` Linus Torvalds
2010-05-19 15:44 ` Nick Piggin
2010-05-19 15:28 ` Miklos Szeredi
2010-05-19 15:32 ` Linus Torvalds
2010-05-19 15:56 ` Miklos Szeredi
2010-05-19 16:01 ` Linus Torvalds
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