From owner-freebsd-net Tue Aug 20 13:57:41 2002 Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 1A01A37B400 for ; Tue, 20 Aug 2002 13:57:38 -0700 (PDT) Received: from iguana.icir.org (iguana.icir.org [192.150.187.36]) by mx1.FreeBSD.org (Postfix) with ESMTP id B739D43E4A for ; Tue, 20 Aug 2002 13:57:37 -0700 (PDT) (envelope-from rizzo@iguana.icir.org) Received: from iguana.icir.org (localhost [127.0.0.1]) by iguana.icir.org (8.12.3/8.11.3) with ESMTP id g7KKvaIb050447; Tue, 20 Aug 2002 13:57:36 -0700 (PDT) (envelope-from rizzo@iguana.icir.org) Received: (from rizzo@localhost) by iguana.icir.org (8.12.3/8.12.3/Submit) id g7KKvaHs050446; Tue, 20 Aug 2002 13:57:36 -0700 (PDT) (envelope-from rizzo) Date: Tue, 20 Aug 2002 13:57:36 -0700 From: Luigi Rizzo To: Andrew Gallatin Cc: freebsd-net@FreeBSD.ORG Subject: Re: m_getcl and end-to-end performance Message-ID: <20020820135736.A50369@iguana.icir.org> References: <15714.27671.533860.408996@grasshopper.cs.duke.edu> <20020820093939.B48541@iguana.icir.org> <15714.39494.661931.882244@grasshopper.cs.duke.edu> <20020820132957.B49141@iguana.icir.org> <15714.43504.493596.791872@grasshopper.cs.duke.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <15714.43504.493596.791872@grasshopper.cs.duke.edu>; from gallatin@cs.duke.edu on Tue, Aug 20, 2002 at 04:43:28PM -0400 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 On Tue, Aug 20, 2002 at 04:43:28PM -0400, Andrew Gallatin wrote: ... > For a driver with lower overhead (fxp), I see ~12K pkts/sec improvemnt > again, SMP and not POLLING) from ~90Kpkts/sec -> to 102Kpkts/sec for > minimally tiny packets. which gets you close to the max throughput for the chip (not the driver!) used by the "fxp" driver, which is: 103kpps with standard TxCB 113kpps with extended TxCB 127kpps if you know the above problem, so do not use buffer descriptors and copy (small) packets into the TxCB don't ask me why, i have no docs and no idea But this is not the only chip which does weird things. Even the 21143, which can go at full speed (148.8kpps), suddenly wastes an extra ~4us when a packet is split across two or more buffers in different descriptors (the "dc" driver has this problem, the "de" driver is slightly smarter and uses the two pointers in each descriptor to point to two buffers, so there you have the problem when you get to 3 buffers). Performance evaluation is a lot of fun :) cheers luigi To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message