From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 25 Sep 2001 16:02:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 25 Sep 2001 16:01:53 -0400 Received: from vasquez.zip.com.au ([203.12.97.41]:43535 "EHLO vasquez.zip.com.au") by vger.kernel.org with ESMTP id ; Tue, 25 Sep 2001 16:01:46 -0400 Message-ID: <3BB0E2B1.6DCCF9DF@zip.com.au> Date: Tue, 25 Sep 2001 13:01:53 -0700 From: Andrew Morton X-Mailer: Mozilla 4.77 [en] (X11; U; Linux 2.4.9-ac12 i686) X-Accept-Language: en MIME-Version: 1.0 To: Chris Newton CC: linux-kernel@vger.kernel.org Subject: Re: excessive interrupts on network cards In-Reply-To: <3BB0E01D@webmail1> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Chris Newton wrote: > > Hi, > > I 'think' the number of interrupts being generated for the network traffic I > monitor, is excessive. Having talked quikly with Donald Becker, he indicated > that I should be seeing a little less than the number of RX/TX packets/s on a > wire, in terms of interrupts/s. That, however, is not what I am seeing. I am > seeing 3 times as many interrupts/s as I am seeing packets/s. > > I have used three network devices to look at the stream I am monitoring, and > it is usually aorund 5K packet/s IN, and 5K out, fed full duplex into a single > 3Com 3c982 (2.4.10 kernel reports that anyways). However, watching: 3c982 is a dual-port server NIC. Is your card dual-port? If not, it's probably a 3c980, and I goofed :) > 'procinfo -D', reports on the order of 30,000 interrupts per second. That does sound rather high. You should compare the interrupt rate with the packet rate from `ifconfig' or /proc/net/dev. Normally, 3c59x will show approx three Tx packets per interrupt and one Rx packet per interrupt. It varies with workload, but it tends to vary in the "good" direction - at higher packet rates, we do more work in a single interrupt and the interrupt-per-packet rate falls.