From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C2116C4360C for ; Tue, 8 Oct 2019 16:32:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7B43420815 for ; Tue, 8 Oct 2019 16:32:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Lqo7vuBv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728465AbfJHQc3 (ORCPT ); Tue, 8 Oct 2019 12:32:29 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:55334 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725966AbfJHQc3 (ORCPT ); Tue, 8 Oct 2019 12:32:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=OhTk70pC2yeqZMH2DCqssp5aW9RjIdmRi6GGW14xL2o=; b=Lqo7vuBvpHV39cxpR+QIsnt+j ksqjOmU1URr2lht7+OewDVvHhNHcTnQMkNLYY6LW/Mib3x5yJggtduk1P+6rQ9RKIspXNa3uXDp1m KoJVKwtViZ8Y2X1kHtUrTsyzqwJNpc34sVXTZTDRLtZeQ/AAvsDZHxGy4gsvwDsgL3papYpuqGxni guPnlvl/gB+JcEoBzYjGmjwOULCtZqKm3AbUaJVSWava8bIT0gLwLCj+GRwQsZN6RIwZOlb1IFMck CpkeyWfpRZuMjTGq7jX0mvcgJ9b1k0Yky+/Pbrs8SuxCTrE9pmkIYccnPzm/R49GnDf3lBDkommYt Nn7O+l/cw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.2 #3 (Red Hat Linux)) id 1iHsPS-0000rl-7p; Tue, 08 Oct 2019 16:32:26 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 5468030034F; Tue, 8 Oct 2019 18:31:32 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 9579220247CA6; Tue, 8 Oct 2019 18:32:23 +0200 (CEST) Date: Tue, 8 Oct 2019 18:32:23 +0200 From: Peter Zijlstra To: "Liang, Kan" Cc: acme@kernel.org, mingo@kernel.org, linux-kernel@vger.kernel.org, jolsa@kernel.org, namhyung@kernel.org, ak@linux.intel.com, vitaly.slobodskoy@intel.com, pavel.gerasimov@intel.com Subject: Re: [PATCH 01/10] perf/core, x86: Add PERF_SAMPLE_LBR_TOS Message-ID: <20191008163223.GE2328@hirez.programming.kicks-ass.net> References: <20191007175910.2805-1-kan.liang@linux.intel.com> <20191007175910.2805-2-kan.liang@linux.intel.com> <20191008083141.GH2294@hirez.programming.kicks-ass.net> <3ac026c3-6b9c-a6c1-2c2b-c7ecdbb22b1d@linux.intel.com> <20191008143850.GB2328@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 08, 2019 at 11:25:01AM -0400, Liang, Kan wrote: > > The perf tool bloody sets the perf_event_attr::branch_sample_type value! > > Of course it knows to expect the TOS field when it asks for it in the > > first place. > > > > Users may generate the perf.data on one machine, and parse the data on > another machine. > If the perf.data is from a new kernel with a new perf tool on one machine, > but users have an old perf tool on another machine to parse it. The old perf > tool doesn't know the exists of TOS field. Feh, the tool should check for unknown input bits in attr. Anyway, the proposed API is horrendous crap, that's just not going to happen.