netdev - Re: zero copy for relay server

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Message-ID: <AANLkTi=GYxOP19HwdD0X33hX-Ku12oxwcX5=-okC9Let@mail.gmail.com>
Date:	Tue, 29 Mar 2011 19:28:51 +0800
From:	Changli Gao <xiaosuo@...il.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	Viral Mehta <Viral.Mehta@...infotech.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: zero copy for relay server

On Tue, Mar 29, 2011 at 12:23 PM, Eric Dumazet <eric.dumazet@...il.com> wrote:
> Le mardi 29 mars 2011 à 10:00 +0800, Changli Gao a écrit :
>> On Tue, Mar 29, 2011 at 2:34 AM, Eric Dumazet <eric.dumazet@...il.com> wrote:
>
>> I think he concerns the overhead of system calls. In order to omit a
>> system call, I think you can implement sth. like this:
>>
>> splice2(infd, outfd, pipefd, ...)
>>
>
> Yes, but given no numbers are given, and no code yet written, I ask the
> question.
>
> Giving 4 file descriptors to a single syscall sounds convoluted.
>

It is a waste of fd using pipe buffer with two fds. In fact, I had
ever posted a patch, which extends pipe(2) to return a O_RDWR fd when
NULL is passed in.

-- 
Regards,
Changli Gao(xiaosuo@...il.com)
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