From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261474AbVFCAt0 (ORCPT ); Thu, 2 Jun 2005 20:49:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261477AbVFCAtZ (ORCPT ); Thu, 2 Jun 2005 20:49:25 -0400 Received: from smtp.lnxw.com ([207.21.185.24]:31240 "EHLO smtp.lnxw.com") by vger.kernel.org with ESMTP id S261474AbVFCAtM (ORCPT ); Thu, 2 Jun 2005 20:49:12 -0400 Date: Thu, 2 Jun 2005 17:54:22 -0700 To: john cooper Cc: "Perez-Gonzalez, Inaky" , dwalker@mvista.com, Esben Nielsen , Ingo Molnar , linux-kernel@vger.kernel.org, sdietrich@mvista.com, rostedt@goodmis.org Subject: Re: [PATCH] Abstracted Priority Inheritance for RT Message-ID: <20050603005422.GA6904@nietzsche.lynx.com> References: <429E9C9A.1030507@timesys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <429E9C9A.1030507@timesys.com> User-Agent: Mutt/1.5.9i From: Bill Huey (hui) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 02, 2005 at 01:43:54AM -0400, john cooper wrote: > That might have been me. The last time I looked at this > specifically, full transitive promotion was being done in > the RT patch. However unlike your attempt at scaling the > lock scope, the RT patch had one lock which coordinated > all mutex dependency traversals system wide. This lock > must be speculatively acquired even before we ascertain > transitive promotion is required. > > So it doesn't scale as well as it could in the case of > large count SMP systems. The response was that of "get > it to work first and then we'll get it to scale" which > is reasonable. Just curious, what do you thinks about the rw-lock comments from Esben in that a real rw-lock can't be deterministic ? bill