From: Ric Wheeler <rwheeler@redhat.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: Zach Brown <zab@redhat.com>,
"J. Bruce Fields" <bfields@fieldses.org>,
Anna Schumaker <schumaker.anna@gmail.com>,
Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux-Fsdevel <linux-fsdevel@vger.kernel.org>,
"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
Trond Myklebust <Trond.Myklebust@netapp.com>,
Bryan Schumaker <bjschuma@netapp.com>,
"Martin K. Petersen" <mkp@mkp.net>, Jens Axboe <axboe@kernel.dk>,
Mark Fasheh <mfasheh@suse.com>, Joel Becker <jlbec@evilplan.org>,
Eric Wong <normalperson@yhbt.net>
Subject: Re: [RFC] extending splice for copy offloading
Date: Thu, 26 Sep 2013 17:23:51 -0400 [thread overview]
Message-ID: <5244A5E7.90808@redhat.com> (raw)
In-Reply-To: <CAJfpegvvWhs+jv2J9kOQrB31PEO3kyn_sLm_e2w9YKp=y6EDhA@mail.gmail.com>
On 09/26/2013 03:53 PM, Miklos Szeredi wrote:
> On Thu, Sep 26, 2013 at 9:06 PM, Zach Brown <zab@redhat.com> wrote:
>
>>> But I'm not sure it's worth the effort; 99% of the use of this
>>> interface will be copying whole files. And for that perhaps we need a
>>> different API, one which has been discussed some time ago:
>>> asynchronous copyfile() returns immediately with a pollable event
>>> descriptor indicating copy progress, and some way to cancel the copy.
>>> And that can internally rely on ->direct_splice(), with appropriate
>>> algorithms for determine the optimal chunk size.
>> And perhaps we don't. Perhaps we can provide this much simpler
>> data-plane interface that works well enough for most everyone and can
>> avoid going down the async rat hole, yet again.
> I think either buffering or async is needed to get good perforrmace
> without too much complexity in the app (which is not good). Buffering
> works quite well for regular I/O, so maybe its the way to go here as
> well.
>
> Thanks,
> Miklos
>
Buffering misses the whole point of the copy offload - the idea is *not* to
read or write the actual data in the most interesting cases which offload the
operation to a smart target device or file system.
Regards,
Ric
next prev parent reply other threads:[~2013-09-26 21:25 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-11 17:06 [RFC] extending splice for copy offloading Zach Brown
2013-09-11 17:06 ` [PATCH 1/3] splice: add DIRECT flag for splicing between files Zach Brown
2013-09-11 17:06 ` [PATCH 2/3] splice: add f_op->splice_direct Zach Brown
2013-09-11 17:06 ` [PATCH 3/3] btrfs: implement .splice_direct extent copying Zach Brown
2013-09-11 21:17 ` [RFC] extending splice for copy offloading Eric Wong
2013-09-16 19:44 ` Rob Landley
2013-09-19 12:59 ` Jeff Layton
2013-09-20 9:49 ` Szeredi Miklos
2013-09-25 18:38 ` Zach Brown
2013-09-25 19:02 ` Anna Schumaker
2013-09-25 19:06 ` Zach Brown
2013-09-25 19:55 ` J. Bruce Fields
2013-09-25 21:07 ` Zach Brown
2013-09-26 8:58 ` Miklos Szeredi
2013-09-26 15:34 ` J. Bruce Fields
2013-09-26 16:46 ` Ric Wheeler
2013-09-26 18:06 ` Miklos Szeredi
2013-09-26 19:06 ` Zach Brown
2013-09-26 19:53 ` Miklos Szeredi
2013-09-26 21:23 ` Ric Wheeler [this message]
2013-09-27 4:47 ` Miklos Szeredi
2013-09-27 14:00 ` Ric Wheeler
2013-09-27 14:39 ` Miklos Szeredi
2013-10-06 8:42 ` Rob Landley
2013-09-26 18:55 ` Zach Brown
2013-09-26 21:26 ` Ric Wheeler
2013-09-27 20:05 ` J. Bruce Fields
2013-09-27 20:50 ` Zach Brown
2013-09-28 5:49 ` Miklos Szeredi
2013-09-28 15:20 ` Myklebust, Trond
2013-09-28 21:20 ` Ric Wheeler
2013-09-30 12:20 ` Miklos Szeredi
2013-09-30 14:34 ` J. Bruce Fields
2013-09-30 14:48 ` Ric Wheeler
2013-09-30 14:51 ` Miklos Szeredi
2013-09-30 14:52 ` Ric Wheeler
2013-09-30 15:24 ` Miklos Szeredi
2013-09-30 14:28 ` Ric Wheeler
2013-09-30 15:33 ` Myklebust, Trond
2013-09-30 15:38 ` Miklos Szeredi
2013-09-30 14:41 ` Ric Wheeler
2013-09-30 15:46 ` Miklos Szeredi
2013-09-30 14:49 ` Ric Wheeler
2013-09-30 15:57 ` Miklos Szeredi
2013-09-30 16:31 ` Miklos Szeredi
2013-09-30 17:17 ` Bernd Schubert
2013-09-30 17:44 ` Myklebust, Trond
2013-09-30 17:48 ` Bernd Schubert
2013-09-30 18:02 ` Myklebust, Trond
2013-09-30 18:49 ` Bernd Schubert
2013-09-30 19:34 ` Myklebust, Trond
2013-09-30 20:00 ` Bernd Schubert
2013-09-30 20:08 ` Ric Wheeler
2013-09-30 20:27 ` Myklebust, Trond
2013-09-30 20:10 ` Myklebust, Trond
2013-10-01 18:42 ` J. Bruce Fields
2013-10-01 19:58 ` Zach Brown
2013-10-02 12:58 ` Jan Kara
2013-10-02 13:31 ` David Lang
2013-12-18 12:41 ` Christoph Hellwig
2013-12-18 17:10 ` Zach Brown
2013-12-18 17:26 ` Anna Schumaker
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