From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261834AbVAHWJ1 (ORCPT ); Sat, 8 Jan 2005 17:09:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261417AbVAHWGr (ORCPT ); Sat, 8 Jan 2005 17:06:47 -0500 Received: from viper.oldcity.dca.net ([216.158.38.4]:61098 "HELO viper.oldcity.dca.net") by vger.kernel.org with SMTP id S261834AbVAHWCw (ORCPT ); Sat, 8 Jan 2005 17:02:52 -0500 Subject: Re: Make pipe data structure be a circular list of pages, rather than From: Lee Revell To: Linus Torvalds Cc: Chris Friesen , Mike Waychison , Alan Cox , Oleg Nesterov , William Lee Irwin III , Linux Kernel Mailing List In-Reply-To: References: <41DE9D10.B33ED5E4@tv-sign.ru> <1105113998.24187.361.camel@localhost.localdomain> <41DEF81B.60905@sun.com> <41DF1F3D.3030006@nortelnetworks.com> <1105220326.24592.98.camel@krustophenia.net> Content-Type: text/plain Date: Sat, 08 Jan 2005 17:02:49 -0500 Message-Id: <1105221769.24592.118.camel@krustophenia.net> Mime-Version: 1.0 X-Mailer: Evolution 2.0.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2005-01-08 at 13:51 -0800, Linus Torvalds wrote: > > On Sat, 8 Jan 2005, Lee Revell wrote: > > > > Many latency critical apps use (tmpfs mounted) FIFO's for IPC; the Linux > > FIFO being one of the fastest known IPC mechanisms. Each client in the > > JACK (http://jackit.sf.net) graph wakes the next one by writing a single > > byte to a FIFO. Ardour's GUI, control, and audio threads interact via a > > similar mechanism. How would you expect this change to impact the inter > > thread wakeup latency? It's confusing when people say "performance", > > meaning "increased throughput albeit with more latency". For many > > people that's a regression. > > I posted the performance numbers in the thread already, and with every > single throughput number I also talked abotu what the latency difference > was. So quite frankly, if you were confused, I suspect it was because you > didn't read them. Tssk, tssk. > How embarassing, I found that message immediately after hitting send. Looks like a big win. I'll try the JACK stress test on it just to make sure. Lee