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From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Nick Piggin <npiggin@suse.de>,
	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 11:51:36 -0400	[thread overview]
Message-ID: <20100519155136.GA2039@Krystal> (raw)
In-Reply-To: <1274281956.26328.776.camel@gandalf.stny.rr.com>

* Steven Rostedt (rostedt@goodmis.org) wrote:
> On Wed, 2010-05-19 at 07:59 -0700, Linus Torvalds wrote:
> > 
> 
> > 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.
> 
> My use case is just to move the data from the ring buffer into a file
> (or network) as fast as possible. It creates a new file and all
> additions are "append to a file".
> 
> I believe Mathieu does the same.
> 
> With me, you are correct.

Same here. My ring buffer only ever use splice() to append at the end of a file
or to the network, and always outputs data in multiples of the page size.

Thanks,

Mathieu

> 
> -- Steve
> 
> 

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com

WARNING: multiple messages have this Message-ID (diff)
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Nick Piggin <npiggin@suse.de>,
	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 11:51:36 -0400	[thread overview]
Message-ID: <20100519155136.GA2039@Krystal> (raw)
In-Reply-To: <1274281956.26328.776.camel@gandalf.stny.rr.com>

* Steven Rostedt (rostedt@goodmis.org) wrote:
> On Wed, 2010-05-19 at 07:59 -0700, Linus Torvalds wrote:
> > 
> 
> > 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.
> 
> My use case is just to move the data from the ring buffer into a file
> (or network) as fast as possible. It creates a new file and all
> additions are "append to a file".
> 
> I believe Mathieu does the same.
> 
> With me, you are correct.

Same here. My ring buffer only ever use splice() to append at the end of a file
or to the network, and always outputs data in multiples of the page size.

Thanks,

Mathieu

> 
> -- Steve
> 
> 

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com

--
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  reply	other threads:[~2010-05-19 15:51 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-18 15:34 Unexpected splice "always copy" behavior observed Mathieu Desnoyers
2010-05-18 15:34 ` Mathieu Desnoyers
2010-05-18 15:51 ` Nick Piggin
2010-05-18 15:51   ` Nick Piggin
2010-05-18 15:56   ` Christoph Lameter
2010-05-18 15:56     ` Christoph Lameter
2010-05-18 16:00     ` Nick Piggin
2010-05-18 16:00       ` Nick Piggin
2010-05-18 16:13       ` Nick Piggin
2010-05-18 16:13         ` Nick Piggin
2010-05-18 15:53 ` Steven Rostedt
2010-05-18 15:53   ` Steven Rostedt
2010-05-18 16:10   ` Steven Rostedt
2010-05-18 16:10     ` Steven Rostedt
2010-05-18 16:25     ` Linus Torvalds
2010-05-18 16:25       ` Linus Torvalds
2010-05-19  6:31       ` Nick Piggin
2010-05-19  6:31         ` Nick Piggin
2010-05-19 14:39         ` Linus Torvalds
2010-05-19 14:39           ` Linus Torvalds
2010-05-19 14:56           ` Steven Rostedt
2010-05-19 14:56             ` Steven Rostedt
2010-05-19 14:59             ` Linus Torvalds
2010-05-19 14:59               ` Linus Torvalds
2010-05-19 15:12               ` Steven Rostedt
2010-05-19 15:12                 ` Steven Rostedt
2010-05-19 15:51                 ` Mathieu Desnoyers [this message]
2010-05-19 15:51                   ` Mathieu Desnoyers
2010-05-19 15:33               ` Miklos Szeredi
2010-05-19 15:33                 ` Miklos Szeredi
2010-05-19 15:45                 ` Steven Rostedt
2010-05-19 15:45                   ` Steven Rostedt
2010-05-19 15:55                   ` Nick Piggin
2010-05-19 15:55                     ` Nick Piggin
2010-05-19 16:01                     ` Mathieu Desnoyers
2010-05-19 16:01                       ` Mathieu Desnoyers
2010-05-19 16:36                     ` Steven Rostedt
2010-05-19 16:36                       ` Steven Rostedt
2010-05-19 15:57                   ` Mathieu Desnoyers
2010-05-19 15:57                     ` Mathieu Desnoyers
2010-05-19 16:27                     ` Nick Piggin
2010-05-19 16:27                       ` Nick Piggin
2010-05-19 19:14                       ` Mathieu Desnoyers
2010-05-19 19:14                         ` Mathieu Desnoyers
2010-05-19 19:31                         ` Linus Torvalds
2010-05-19 19:31                           ` Linus Torvalds
2010-05-19 21:49                           ` Mathieu Desnoyers
2010-05-19 21:49                             ` Mathieu Desnoyers
2010-05-20  0:04                             ` Linus Torvalds
2010-05-20  0:04                               ` Linus Torvalds
2010-05-20  1:56                               ` Mathieu Desnoyers
2010-05-20  1:56                                 ` Mathieu Desnoyers
2010-05-20 14:18                                 ` Linus Torvalds
2010-05-20 14:18                                   ` Linus Torvalds
2010-05-20 14:18                                   ` Linus Torvalds
2010-05-19 20:59               ` Rick Sherm
2010-05-19 20:59                 ` Rick Sherm
2010-05-19 15:17           ` Nick Piggin
2010-05-19 15:17             ` Nick Piggin
2010-05-19 15:30             ` Linus Torvalds
2010-05-19 15:30               ` Linus Torvalds
2010-05-19 15:44               ` Nick Piggin
2010-05-19 15:44                 ` Nick Piggin
2010-05-19 15:28           ` Miklos Szeredi
2010-05-19 15:28             ` Miklos Szeredi
2010-05-19 15:32             ` Linus Torvalds
2010-05-19 15:32               ` Linus Torvalds
2010-05-19 15:56               ` Miklos Szeredi
2010-05-19 15:56                 ` Miklos Szeredi
2010-05-19 16:01                 ` Linus Torvalds
2010-05-19 16:01                   ` Linus Torvalds

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