From owner-freebsd-net@FreeBSD.ORG Mon Oct 25 13:37:26 2004 Return-Path: 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 C408D16A4CE for ; Mon, 25 Oct 2004 13:37:26 +0000 (GMT) Received: from exchange.sandvine.com (sandvine.com [199.243.201.138]) by mx1.FreeBSD.org (Postfix) with ESMTP id 573A243D54 for ; Mon, 25 Oct 2004 13:37:26 +0000 (GMT) (envelope-from don@sandvine.com) X-MimeOLE: Produced By Microsoft Exchange V6.0.6556.0 content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Date: Mon, 25 Oct 2004 09:37:25 -0400 Message-ID: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Underutilisation of CPU --- am I PCI bus bandwidth limited? Thread-Index: AcS6MEOg7GvNpXSNRF+ty+EHWjEBuwAZ3jKA From: "Don Bowman" To: , Subject: RE: Underutilisation of CPU --- am I PCI bus bandwidth limited? X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 Oct 2004 13:37:26 -0000 From: lukem.freebsd@cse.unsw.edu.au >=20 ... >=20 > This is rather confusing, as I cannot tell if the system is=20 > IO bound or CPU=20 > bound. Certainly I would not have expected the 133/64 PCI bus=20 > to be saturated=20 > given that peak throughput is around 550Mbit/s with 1024-byte=20 > packets. (Such a=20 > low figure is not unexpected given there are 2 syscalls per packet). You may find you have not loaned the em driver enough buffers, (max_rxd, max_txd). you may find you want to use device polling, poll on idle, and play with the polling parameters. In this config i have achieved ~2Gbps of throughput with these large packets, so i know it can be done.