From mboxrd@z Thu Jan 1 00:00:00 1970 From: jamal Subject: Re: [PATCH v3] net: batch skb dequeueing from softnet input_pkt_queue Date: Wed, 14 Apr 2010 08:28:21 -0400 Message-ID: <1271248101.3943.67.camel@bigi> References: <1271238738-8386-1-git-send-email-xiaosuo@gmail.com> <1271246304.3943.60.camel@bigi> Reply-To: hadi@cyberus.ca Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: "David S. Miller" , Eric Dumazet , netdev@vger.kernel.org To: Changli Gao Return-path: Received: from mail-qy0-f189.google.com ([209.85.221.189]:59933 "EHLO mail-qy0-f189.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753365Ab0DNM2Z (ORCPT ); Wed, 14 Apr 2010 08:28:25 -0400 Received: by qyk27 with SMTP id 27so100686qyk.23 for ; Wed, 14 Apr 2010 05:28:23 -0700 (PDT) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Wed, 2010-04-14 at 20:13 +0800, Changli Gao wrote: > On Wed, Apr 14, 2010 at 7:58 PM, jamal wrote: > No extra IPI is needed. > > + qlen = queue->input_pkt_queue.qlen + queue->processing_queue.qlen; > + if (qlen <= netdev_max_backlog) { > + if (qlen) { > > the packets in processing_queue are counted too. Ok - Looks reasonable. > > IPIs add to latency (refer to my other email). Did you test this > > to reach some conclusion that it improves thing or was it just by > > inspection? > > > > :( only insepection. I am probably being pushy, but one simple test for latency of single flow is: from machine 1, send ping -f on rps machine: Base test: no rps on ( a fresh boot with no sysctls should do fine) Test 1: irq affinity on cpuX, rps to cpuY Test 2: repeat test1 with your change. It should show no difference between test1 and 2. If it shows improvement better - but showing worse latency is bad. cheers, jamal