From: Jeff Garzik <jeff@garzik.org>
To: hail-devel@vger.kernel.org
Cc: Steven Dake <sdake@redhat.com>
Subject: Re: [PATCH 1/3 v2] chunkd: remove sendfile(2) zero-copy support
Date: Sun, 18 Jul 2010 19:23:38 -0400 [thread overview]
Message-ID: <4C438CFA.5040703@garzik.org> (raw)
In-Reply-To: <4C4389D1.6000201@garzik.org>
On 07/18/2010 07:10 PM, Jeff Garzik wrote:
> On 07/17/2010 11:45 PM, Steven Dake wrote:
>> On 07/16/2010 10:46 PM, Jeff Garzik wrote:
>>> chunkd: remove sendfile(2) zero-copy support
>>>
>>> chunkd will be soon checksumming data in main memory. That removes
>>> the utility of a zero-copy interface which bypasses the on-heap
>>> data requirement.
>>>
>>> Signed-off-by: Jeff Garzik<jgarzik@redhat.com>
>
>> May be able to use vmsplice with sendfile (if linux is only target
>> platform). Haven't tried it myself, but the operations look interesting
>> at achieving zero copy with sockets from memory addresses.
As an aside, Project Hail -is- intended to be portable to other
operating systems. That said, I happily use OS-specific features if
they have a measurable impact on our core code paths.
Another OS-specific feature I plan on using, for example, is
sync_file_range(2) for large objects. We can make use of the technique
used by MythTV for streaming, which Linus describes here:
http://marc.info/?l=linux-kernel&m=127429771726842&w=2
http://marc.info/?l=linux-kernel&m=127431438118461&w=2
next prev parent reply other threads:[~2010-07-18 23:23 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-17 5:46 [PATCH 0/3 v2] chunkd on-disk checksumming Jeff Garzik
2010-07-17 5:46 ` [PATCH 1/3 v2] chunkd: remove sendfile(2) zero-copy support Jeff Garzik
2010-07-18 3:45 ` Steven Dake
2010-07-18 23:10 ` Jeff Garzik
2010-07-18 23:23 ` Jeff Garzik [this message]
2010-07-17 5:47 ` [PATCH 2/3 v2] chunkd: Add checksum table to on-disk format, one sum per 64k of data Jeff Garzik
2010-07-17 5:47 ` [PATCH 3/3 v2] [chunkd] match network buffer size to checksum buffer size (64k) Jeff Garzik
2010-07-18 7:09 ` [PATCH 4/4] chunkd checksums each block, as it is read from disk Jeff Garzik
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