From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: Bug 7596 - Potential performance bottleneck for Linxu TCP Date: Tue, 19 Dec 2006 21:15:51 -0800 (PST) Message-ID: <20061219.211551.112620476.davem@davemloft.net> References: <20061219.185525.41636407.davem@davemloft.net> <20061219211124.061b5c2d@localhost.localdomain> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: herbert@gondor.apana.org.au, mingo@elte.hu, akpm@osdl.org, wenji@fnal.gov, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:41114 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S932949AbWLTFQU (ORCPT ); Wed, 20 Dec 2006 00:16:20 -0500 To: shemminger@osdl.org In-Reply-To: <20061219211124.061b5c2d@localhost.localdomain> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Stephen Hemminger Date: Tue, 19 Dec 2006 21:11:24 -0800 > It was the realtime/normal comments that piqued my interest. > Perhaps we should either tweak process priority or remove > the comments. I mentioned that to Linus once and he said the entire idea was bogus. With the recent tcp_recvmsg() preemption issue thread, I agree with his sentiments even more than I did previously. What needs to happen is to liberate the locking so that input packet processing can occur in parallel with tcp_recvmsg(), instead of doing this bogus backlog thing which can wedge TCP ACK processing for an entire quantum if we take a kernel preemption while the process has the socket lock held.