Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161039AbVJHBid (ORCPT ); Fri, 7 Oct 2005 21:38:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932614AbVJHBid (ORCPT ); Fri, 7 Oct 2005 21:38:33 -0400 Received: from fmr21.intel.com ([143.183.121.13]:51434 "EHLO scsfmr001.sc.intel.com") by vger.kernel.org with ESMTP id S932108AbVJHBic (ORCPT ); Fri, 7 Oct 2005 21:38:32 -0400 Message-Id: <200510080138.j981cOg04614@unix-os.sc.intel.com> From: "Chen, Kenneth W" To: "'Jon Burgess'" Cc: "Andi Kleen" , , Subject: RE: kernel performance update - 2.6.14-rc3 Date: Fri, 7 Oct 2005 18:38:24 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook, Build 11.0.6353 Thread-Index: AcXLojmAMZ9UetKWSp2NZplmfEEEXQABXMBw In-Reply-To: <434717B7.30505@uklinux.net> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1191 Lines: 27 Jon Burgess wrote on Friday, October 07, 2005 5:50 PM > "Chen, Kenneth W" writes: > > Even though > > softirq is invoked at the end of dev_queue_xmit() via local_bh_enable(), > > not all execution of softirq will result a __wake_up(). With higher > > HZ rate, timer interrupt is more frequent and thus more softirq > > invocation and leads to more __wake_up(), which then takes us to higher > > throughput because cpu spend less time in idle. > > Since the loopback xmit->rx path probably isn't being called in > interrupt context might something like the patch below be needed? > > Please forgive me if this is wrong, i've not even tried compiling > this change let alone tested it. I don't think this patch has any effect. dev_queue_xmit turns off local_bh when calling loopback_xmit, so calls to do_softirq from netif_rx_ni Will be a noop since do_softirq immediately return upon seeing in_interrupt(). - Ken - 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/