From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262725AbTLQAj1 (ORCPT ); Tue, 16 Dec 2003 19:39:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262740AbTLQAj1 (ORCPT ); Tue, 16 Dec 2003 19:39:27 -0500 Received: from fmr05.intel.com ([134.134.136.6]:43732 "EHLO hermes.jf.intel.com") by vger.kernel.org with ESMTP id S262725AbTLQAjY convert rfc822-to-8bit (ORCPT ); Tue, 16 Dec 2003 19:39:24 -0500 content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT X-MimeOLE: Produced By Microsoft Exchange V6.0.6487.1 Subject: RE: [CFT][RFC] HT scheduler Date: Tue, 16 Dec 2003 16:38:28 -0800 Message-ID: <7F740D512C7C1046AB53446D372001736187C8@scsmsx402.sc.intel.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [CFT][RFC] HT scheduler Thread-Index: AcPENHrpQHljw5B7Sm6O/nvHOLWIrAAANjJw From: "Nakajima, Jun" To: "Davide Libenzi" , "Linus Torvalds" Cc: "Jamie Lokier" , "Nick Piggin" , "bill davidsen" , "Linux Kernel Mailing List" X-OriginalArrivalTime: 17 Dec 2003 00:38:29.0077 (UTC) FILETIME=[1710F050:01C3C436] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > You forgot the one where no HT knowledge can be used for optimizations. > > - Asserting the CPU's #LOCK pin to take control of the system bus. That in > MP system translate into the signaling CPU taking full control of the > system bus until the pin is deasserted. > It is not the case with UP (single socket) using HT, where some optimization for locks could be available. But you still need locks for the logical processors. Jun > -----Original Message----- > From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel- > owner@vger.kernel.org] On Behalf Of Davide Libenzi > Sent: Tuesday, December 16, 2003 4:25 PM > To: Linus Torvalds > Cc: Jamie Lokier; Nick Piggin; bill davidsen; Linux Kernel Mailing List > Subject: Re: [CFT][RFC] HT scheduler > > On Tue, 16 Dec 2003, Linus Torvalds wrote: > > > I bet it is. In a big way. > > > > The lock does two independent things: > > - it tells the core that it can't just crack up the load and store. > > - it also tells other memory ops that they can't re-order around it. > > You forgot the one where no HT knowledge can be used for optimizations. > > - Asserting the CPU's #LOCK pin to take control of the system bus. That in > MP system translate into the signaling CPU taking full control of the > system bus until the pin is deasserted. > > > > - Davide > > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/