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Date: Sat, 20 Jan 2001 22:58:10 +0100
From: Edgar Toernig <froese@gmx.de>
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To: Michael Lindner <mikel@att.net>
CC: Chris Wedgwood <cw@f00f.org>, Dan Maas <dmaas@dcine.com>,
        linux-kernel@vger.kernel.org
Subject: Re: PROBLEM: select() on TCP socket sleeps for 1 tick even if data 
 available
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Michael Lindner wrote:
>[...]
>                 send(s, ".", 1, 0);
>[...]
>         while (select(r+1, &readfds, 0, 0, 0) > 0) {
>[...]
>[select returns only after about 1 HZ]

Ever heard of nagle?  (If not, there's a long thread about
it on the mailing list *g*)

It's not the select that waits. It's a delay in the tcp send
path waiting for more data.  Try disabling it:

	int f=1;
	setsockopt(s, SOL_TCP, TCP_NODELAY, &f, sizeof(f));

Ciao, ET.

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