From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765760AbXJPQww (ORCPT ); Tue, 16 Oct 2007 12:52:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757922AbXJPQwo (ORCPT ); Tue, 16 Oct 2007 12:52:44 -0400 Received: from srv5.dvmed.net ([207.36.208.214]:47078 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757519AbXJPQwo (ORCPT ); Tue, 16 Oct 2007 12:52:44 -0400 Message-ID: <4714EC54.7080808@garzik.org> Date: Tue, 16 Oct 2007 12:52:36 -0400 From: Jeff Garzik User-Agent: Thunderbird 2.0.0.5 (X11/20070727) MIME-Version: 1.0 To: Ingo Molnar CC: David Miller , linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, shemminger@linux-foundation.org Subject: Re: [patch] forcedeth: fix the NAPI poll function References: <20071015112430.GA30006@elte.hu> <20071015.125731.79447899.davem@davemloft.net> <20071015220357.GA7174@elte.hu> <20071015220720.GA16101@elte.hu> <20071015223009.GA27425@elte.hu> <4713EC59.4010106@pobox.com> <20071016054236.GA27906@elte.hu> <47145075.1080003@garzik.org> <20071016064026.GA9578@elte.hu> <47146593.2060909@garzik.org> <20071016074943.GA24481@elte.hu> In-Reply-To: <20071016074943.GA24481@elte.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.4 (----) X-Spam-Report: SpamAssassin version 3.1.9 on srv5.dvmed.net summary: Content analysis details: (-4.4 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > * Jeff Garzik wrote: > >>> FYI, looks good so far, ontop of Linus' latest -git tree. >>> >>> btw., one thing i always found weird about forcedeth is that it >>> generates an extra ~100 irqs per second even when there's no network >>> traffic: >>> >>> 11: 89752 XT-PIC-XT eth0 >>> 11: 89854 XT-PIC-XT eth0 >>> 11: 89955 XT-PIC-XT eth0 >>> 11: 90056 XT-PIC-XT eth0 >>> 11: 90157 XT-PIC-XT eth0 >>> >>> (irq count snapshot every second). Just in case it's easy to fix ... >> >> May I presume that behavior occurs in both mainline and my fe-lock >> branch? > > correct. Any chance of getting a quick comparison of forcedeth CPU usage in your setup, between old driver and fe-lock driver? I'm curious about the effects of fe-lock on CPU usage, which NAPI is known to perturb (in positive or negative directions, depending on conditions). I presume both drivers can work at wire speed, sans any "too many iterations" problems... >> That is likely the NIC's timer irq, which is programmed to kick the >> irq handler every so often. DEV_NEED_TIMERIRQ is a starting point, as >> well as "Known bugs" at the top of forcedeth.c, if you're curious. >> >> I'm _betting_ that some of that can be eliminated, but we'll see... > > ok. Was just a FYI - you were looking for feedback :-) Thanks! :) Jeff