From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932083AbVHLU5N (ORCPT ); Fri, 12 Aug 2005 16:57:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932084AbVHLU5N (ORCPT ); Fri, 12 Aug 2005 16:57:13 -0400 Received: from e1.ny.us.ibm.com ([32.97.182.141]:29623 "EHLO e1.ny.us.ibm.com") by vger.kernel.org with ESMTP id S932083AbVHLU5M (ORCPT ); Fri, 12 Aug 2005 16:57:12 -0400 Date: Fri, 12 Aug 2005 13:57:44 -0700 From: "Paul E. McKenney" To: Ingo Molnar Cc: Lee Revell , linux-kernel@vger.kernel.org, dipankar@in.ibm.com, rusty@au1.ibm.com, bmark@us.ibm.com, Thomas Gleixner , Andrew Morton Subject: Re: [RFC,PATCH] Use RCU to protect tasklist for unicast signals Message-ID: <20050812205744.GE1297@us.ibm.com> Reply-To: paulmck@us.ibm.com References: <20050810171145.GA1945@us.ibm.com> <20050811095634.GA19342@elte.hu> <1123812057.26878.9.camel@mindpipe> <20050812063600.GC13397@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050812063600.GC13397@elte.hu> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 12, 2005 at 08:36:00AM +0200, Ingo Molnar wrote: > > * Lee Revell wrote: > > > Doesn't this fix the longest latency we were seeing with > > PREEMPT_DESKTOP, I don't have a trace handy but the upshot was "signal > > delivery must remain atomic on !PREEMPT_RT"? > > yes - although Paul's patch converts only a portion of the signal code > to RCU-read-lock, so i'd expect there to be other latencies too. Might > be worth a test (once we've sorted out the HRT build bugs). And there remains the question of how much of the benefit remains after I handle the corner cases... :-/ Thanx, Paul