From owner-freebsd-hackers Fri Nov 30 13: 0:43 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by hub.freebsd.org (Postfix) with ESMTP id DDE4437B61F for ; Fri, 30 Nov 2001 13:00:34 -0800 (PST) Received: (from dillon@localhost) by apollo.backplane.com (8.11.6/8.9.1) id fAUKxrI19553; Fri, 30 Nov 2001 12:59:53 -0800 (PST) (envelope-from dillon) Date: Fri, 30 Nov 2001 12:59:53 -0800 (PST) From: Matthew Dillon Message-Id: <200111302059.fAUKxrI19553@apollo.backplane.com> To: Mike Silbersack Cc: Leo Bicknell , Subject: Re: TCP Performance Graphs References: Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG :I don't think anyone's doubting the importance of larger windows; it's :just that we can't do much increasing until they're dynamic. : :That being said, Matt did post a patch which implements socket buffer :autoscaling a few months back. I've been meaning to review it, but :haven't had the time. If you can give it some good testing and prove that :it provides better performance in most cases (and hopefully no :regressions), I suspect that might provide the momentum to get it :looked at by more people and committed. : :Mike "Silby" Silbersack One of the things that came out of that conversation, however, was that it should be safe to increase the receive-side window, because programs typically drain the receive buffers the moment data comes in. So I think we can safely increase the dfeault net.inet.tcp.recvspace from 16384 to 32768 immediately. The transmit side requires more thought. I did write that patch, and it does work, but it's too messy for my tastes. I would personally much rather rewrite it to (A) fix the RTT stored in the route tables and (B) adjust the transmit window based on that, which is a much less sophisticated patch (and less messy), but ought to work quite well in regards to transmit buffer management. After I figure out this 80K/sec problem I'll revisit the transmit-side buffer limiting based on my new proposal above. -Matt Matthew Dillon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message