Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752345AbaJXHr2 (ORCPT ); Fri, 24 Oct 2014 03:47:28 -0400 Received: from mga01.intel.com ([192.55.52.88]:11245 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751432AbaJXHr0 (ORCPT ); Fri, 24 Oct 2014 03:47:26 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,778,1406617200"; d="scan'208";a="610477671" From: Alexander Shishkin To: Peter Zijlstra Cc: Ingo Molnar , linux-kernel@vger.kernel.org, Robert Richter , Frederic Weisbecker , Mike Galbraith , Paul Mackerras , Stephane Eranian , Andi Kleen , kan.liang@intel.com, adrian.hunter@intel.com, acme@infradead.org Subject: Re: [PATCH v5 11/20] x86: perf: Intel PT and LBR/BTS are mutually exclusive In-Reply-To: <20141022141547.GO12706@worktop.programming.kicks-ass.net> References: <1413207948-28202-1-git-send-email-alexander.shishkin@linux.intel.com> <1413207948-28202-12-git-send-email-alexander.shishkin@linux.intel.com> <20141022141547.GO12706@worktop.programming.kicks-ass.net> User-Agent: Notmuch/0.17+49~gaa57e9d (http://notmuchmail.org) Emacs/24.3.1 (x86_64-pc-linux-gnu) Date: Fri, 24 Oct 2014 10:47:16 +0300 Message-ID: <87bnp13o57.fsf@ashishki-desk.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Peter Zijlstra writes: > On Mon, Oct 13, 2014 at 04:45:39PM +0300, Alexander Shishkin wrote: >> Intel PT cannot be used at the same time as LBR or BTS and will cause a >> general protection fault if they are used together. In order to avoid >> fixing up GPs in the fast path, instead we use flags to indicate that >> that one of these is in use so that the other avoids MSR access altogether. >> > > Yeah, don't like this. Like I've said many times before we should simply > disallow creating PT events when there are LBR events and vice versa. Ok, I must have misunderstood you before. This makes things a bit easier. Regards, -- Alex -- 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/