From owner-freebsd-net  Thu Feb  1 16:51:52 2001
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Date: Fri, 2 Feb 2001 00:50:18 +0000
From: Tony Finch <dot@dotat.at>
To: David Xu <davidx@viasoft.com.cn>
Cc: Kris Kennaway <kris@obsecurity.org>, bsddiy <bsddiy@163.net>,
	freebsd-net@FreeBSD.ORG
Subject: Re: sendfile()
Message-ID: <20010202005018.Y70673@hand.dotat.at>
References: <1217774688.20010201133139@163.net> <20010201023825.A71975@xor.obsecurity.org> <20010201180010.Q70673@hand.dotat.at> <001d01c08cb1$9c445d80$6201a8c0@William>
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David Xu <davidx@viasoft.com.cn> wrote:
>
>but as I know, it seems TCP_NOPUSH is mainly used for TTCP, right?

That's what it was designed for.

>the idea behind TCP_CORK is it buffers any small data segment user
>program sending until these segments full fills a max TCP packet,
>then the packet is sent,

TCP_NOPUSH is the same

>web servers always send many very small HTTP headers, cause lots of
>small packets sent out, TCP_CORK can increase network performance.

No, web servers are very careful to reduce the number of packets
required for a response. TCP_CORK exists to avoid two bad packet
boundaries per request: one between the header and the body, and one
between the body and the next response. FreeBSD's sendfile allows you
to easily optimise the beginning of the response; optimising the
transition from one response to the next is harder.

Tony.
-- 
f.a.n.finch    fanf@covalent.net    dot@dotat.at
"If I didn't see it with my own eyes I would never have believed it!"


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