From owner-freebsd-net Thu Oct 11 18:30: 7 2001 Delivered-To: freebsd-net@freebsd.org Received: from InterJet.dellroad.org (adsl-63-194-81-26.dsl.snfc21.pacbell.net [63.194.81.26]) by hub.freebsd.org (Postfix) with ESMTP id 8539737B403 for ; Thu, 11 Oct 2001 18:30:03 -0700 (PDT) Received: from arch20m.dellroad.org (arch20m.dellroad.org [10.1.1.20]) by InterJet.dellroad.org (8.9.1a/8.9.1) with ESMTP id SAA21285; Thu, 11 Oct 2001 18:16:15 -0700 (PDT) Received: (from archie@localhost) by arch20m.dellroad.org (8.11.3/8.11.3) id f9C1GEv18196; Thu, 11 Oct 2001 18:16:14 -0700 (PDT) (envelope-from archie) From: Archie Cobbs Message-Id: <200110120116.f9C1GEv18196@arch20m.dellroad.org> Subject: Re: strange results with increased net.inet.ip.intr_queue_maxlen In-Reply-To: <5.1.0.14.0.20011011164834.0728c2e0@marble.sentex.ca> "from Mike Tancsa at Oct 11, 2001 04:50:42 pm" To: Mike Tancsa Date: Thu, 11 Oct 2001 18:16:14 -0700 (PDT) Cc: rizzo@aciri.org, freebsd-net@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL82 (25)] MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Mike Tancsa writes: > > > net.inet.ip.intr_queue_maxlen from 50 to 100. and there didnt seem to be > > > any positive results in terms of lessening the rate of > > > net.inet.ip.intr_queue_drops. > > > >This is consistent with the situation where packets are received > >at a rate faster than they are being consumed. No matter how big > >your queue is, it's going to fill up eventually and overflow, and > >all you're doing by increasing the queue length is adding latency > >to all of those packets that you do process. > > Hi, thanks for the info. But wont I still pay a price, presumably at the > application layer for any packets that are lost and retransmitted ? Apart > from pinging the other side of the OC-3 or ethernet connection and > measuring the response time, how can I see how much latency is added by > increasing these buffers ? If the forwarding path is maxed out, then it is the application layer's responsibility to back off (think TCP). Pinging is an excellent way to determine latency. -Archie __________________________________________________________________________ Archie Cobbs * Packet Design * http://www.packetdesign.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message