From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267584AbUHEHTS (ORCPT ); Thu, 5 Aug 2004 03:19:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267586AbUHEHTR (ORCPT ); Thu, 5 Aug 2004 03:19:17 -0400 Received: from fw.osdl.org ([65.172.181.6]:9901 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S267584AbUHEHTQ (ORCPT ); Thu, 5 Aug 2004 03:19:16 -0400 Date: Thu, 5 Aug 2004 00:17:37 -0700 From: Andrew Morton To: Ulrich Drepper Cc: inaky.perez-gonzalez@intel.com, linux-kernel@vger.kernel.org, robustmutexes@lists.osdl.org, rusty@rustcorp.com.au, mingo@elte.hu, jamie@shareable.org Subject: Re: [RFC/PATCH] FUSYN Realtime & robust mutexes for Linux, v2.3.1 Message-Id: <20040805001737.78afb0d6.akpm@osdl.org> In-Reply-To: <4111DC8C.7050504@redhat.com> References: <20040804232123.3906dab6.akpm@osdl.org> <4111DC8C.7050504@redhat.com> X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ulrich Drepper wrote: > > Andrew Morton wrote: > > > This fixes what appear to be some fairly significant shortcomings. What do > > the futex and NPTL people have to say about the gravity of the problems > > which this solves, and the offered implementation? > > This code will not be suppoerted by the glibc code. Using these > primitives would mean significant slowdown of all operations and this > for problems which only a few people have. How large is the slowdown, and on what workloads? > I asked to get the useful > parts of the code to be made available using the current futex interface > (robust mutexes are useful) Passing the lock to a non-rt task when there's an rt-task waiting for it seems pretty poor form, too.