Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422673AbWHSBb6 (ORCPT ); Fri, 18 Aug 2006 21:31:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751621AbWHSBb5 (ORCPT ); Fri, 18 Aug 2006 21:31:57 -0400 Received: from smtp.osdl.org ([65.172.181.4]:3476 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1751267AbWHSBb4 (ORCPT ); Fri, 18 Aug 2006 21:31:56 -0400 Message-ID: <44E7BB7F.7030204@osdl.org> Date: Sat, 19 Aug 2006 18:31:43 -0700 From: Stephen Hemminger User-Agent: Thunderbird 1.5.0.5 (Windows/20060719) MIME-Version: 1.0 To: Arnd Bergmann CC: linuxppc-dev@ozlabs.org, akpm@osdl.org, James K Lewis , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Jeff Garzik , Jens Osterkamp , David Miller Subject: Re: [RFC] HOWTO use NAPI to reduce TX interrupts References: <20060818220700.GG26889@austin.ibm.com> <20060818222657.GL26889@austin.ibm.com> <200608190103.05649.arnd@arndb.de> <200608190256.26373.arnd@arndb.de> In-Reply-To: <200608190256.26373.arnd@arndb.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1201 Lines: 31 Arnd Bergmann wrote: > On Saturday 19 August 2006 01:03, Arnd Bergmann wrote: > >> Someone should probably document that in >> Documentation/networking/NAPI_HOWTO.txt, I might end up doing that >> once we get it right for spidernet >> The reason reclaim via poll() is efficient is because it avoid causing a softirq that is necessary when skb_free_irq() is done. Instead it reuses the softirq from the poll() routine. Like all Rx NAPI, using poll() for reclaim means: + aggregating multiple frames in one irq - increased overhead of twiddling with the IRQ mask - more ways to get driver stuck Some drivers do all their irq work in the poll() routine (including PHY handling). This is good if reading the IRQ status does an auto mask operation. The whole NAPI documentation area is a mess and needs a good writer to do some major restructuring. It should also be split into reference information, tutorial and guide sections. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/