From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roland Dreier Subject: Re: [RFC] HOWTO use NAPI to reduce TX interrupts Date: Mon, 21 Aug 2006 17:29:05 -0700 Message-ID: References: <44E7BB7F.7030204@osdl.org> <200608191325.19557.arnd@arndb.de> <20060821235244.GJ5427@austin.ibm.com> <20060821.165616.107936004.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linas@austin.ibm.com, arnd@arndb.de, shemminger@osdl.org, akpm@osdl.org, netdev@vger.kernel.org, jklewis@us.ibm.com, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, Jens.Osterkamp@de.ibm.com, jgarzik@pobox.com Return-path: Received: from sj-iport-1-in.cisco.com ([171.71.176.70]:29779 "EHLO sj-iport-1.cisco.com") by vger.kernel.org with ESMTP id S1751309AbWHVA3J (ORCPT ); Mon, 21 Aug 2006 20:29:09 -0400 To: David Miller In-Reply-To: <20060821.165616.107936004.davem@davemloft.net> (David Miller's message of "Mon, 21 Aug 2006 16:56:16 -0700 (PDT)") Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org David> Don't touch interrupts until both RX and TX queue work is David> fullydepleted. You seem to have this notion that RX and TX David> interrupts are seperate. They aren't, even if your device David> can generate those events individually. Whatever interrupt David> you get, you shut down all interrupt sources and schedule David> the ->poll(). Then ->poll() does something like: This is a digression from spidernet, but what if a device is able to generate separate MSIs for TX and RX? Some people from IBM have suggested that it is beneficial for throughput to handle TX work and RX work for IP-over-InfiniBand in parallel on separate CPUs, and handling everything through the ->poll() method would defeat this. - R.