Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262660AbVENIck (ORCPT ); Sat, 14 May 2005 04:32:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262706AbVENIck (ORCPT ); Sat, 14 May 2005 04:32:40 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:9856 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S262660AbVENIcj (ORCPT ); Sat, 14 May 2005 04:32:39 -0400 Subject: Re: Hyper-Threading Vulnerability From: Arjan van de Ven To: linux@horizon.com Cc: linux-kernel@vger.kernel.org In-Reply-To: <20050513225135.20005.qmail@science.horizon.com> References: <20050513225135.20005.qmail@science.horizon.com> Content-Type: text/plain Date: Sat, 14 May 2005 10:03:39 +0200 Message-Id: <1116057819.6007.1.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.0.4 (2.0.4-4) Content-Transfer-Encoding: 7bit X-Spam-Score: 3.7 (+++) X-Spam-Report: SpamAssassin version 2.63 on pentafluge.infradead.org summary: Content analysis details: (3.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 1.1 RCVD_IN_DSBL RBL: Received via a relay in list.dsbl.org [] 2.5 RCVD_IN_DYNABLOCK RBL: Sent directly from dynamic IP address [80.57.133.107 listed in dnsbl.sorbs.net] 0.1 RCVD_IN_SORBS RBL: SORBS: sender is listed in SORBS [80.57.133.107 listed in dnsbl.sorbs.net] X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 868 Lines: 18 On Fri, 2005-05-13 at 22:51 +0000, linux@horizon.com wrote: > If RDTSC is too annoying to disable, just interpret the same flag as a > "schedule me solo" flag that prevents scheduling anything else (at least, > not sharing the same ->mm) on the other virtual processor. (Of course, > the time should count double for scheduler fairness purposes.) rdtsc is so unreliable on current hardware that no userspace app should be using it anyway; it's not synchronized on SMP, powermanagement impacts the rate of the ticks all the time etc etc. Basically it's worthless on modern machines for anything but in-kernel busy loops. - 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/