Date: Fri, 09 Mar 2001 09:59:38 +0100 (MET) From: dada@sbox.tugraz.at To: freebsd-net@freebsd.org Cc: mkamm@gmx.net Subject: backlog of listen(2) Message-ID: <984128378.3aa89b7ab728f@sbox.tugraz.at>
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Just curious: I noticed that FreeBSD and NetBSD will give you a 50% longer listen queue than what was requested with the second argument of listen(2). (You get trunc(N*3/2)+1 for backlog=N). Thus with the default SOMAXCONN of 128 (this is settable with a sysctl) we actually have a listen queue of 193 connections. (OpenBSD dropped the "divide by two" and gives you 200% more than requested.) Obviously this doesn´t break anything - it has been this way at least since BSD 4.4 Lite - but it makes me curious. Does anybody know why this was implemented other than it is documented? Btw, Linux counts exactly (gives 2*N+1) but since 2.2 only completed connections are counted. TIA, Martin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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