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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 E1260C43143 for ; Mon, 1 Oct 2018 06:25:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ABD0D2083C for ; Mon, 1 Oct 2018 06:25:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ABD0D2083C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728827AbeJANB4 (ORCPT ); Mon, 1 Oct 2018 09:01:56 -0400 Received: from mga09.intel.com ([134.134.136.24]:61968 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727693AbeJANB4 (ORCPT ); Mon, 1 Oct 2018 09:01:56 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 30 Sep 2018 23:25:47 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,326,1534834800"; d="scan'208";a="94922403" Received: from linux.intel.com ([10.54.29.200]) by fmsmga001.fm.intel.com with ESMTP; 30 Sep 2018 23:25:47 -0700 Received: from [10.125.252.7] (abudanko-mobl.ccr.corp.intel.com [10.125.252.7]) by linux.intel.com (Postfix) with ESMTP id 9D287580409; Sun, 30 Sep 2018 23:25:43 -0700 (PDT) From: Alexey Budankov Subject: Re: [RFC 0/5] perf: Per PMU access controls (paranoid setting) To: Jann Horn Cc: Andi Kleen , Mark Rutland , Thomas Gleixner , tursulin@ursulin.net, kernel list , tvrtko.ursulin@linux.intel.com, Peter Zijlstra , the arch/x86 maintainers , "H . Peter Anvin" , acme@kernel.org, alexander.shishkin@linux.intel.com, jolsa@redhat.com, namhyung@kernel.org, maddy@linux.vnet.ibm.com, Kees Cook References: <20180919122751.12439-1-tvrtko.ursulin@linux.intel.com> <20180928164111.i6nba2j6mnegwslw@lakrids.cambridge.arm.com> <20180928172340.GA32651@tassilo.jf.intel.com> <20180928174016.i7d24puv7y3jwzf6@lakrids.cambridge.arm.com> <20180928204930.GC32651@tassilo.jf.intel.com> <20180928205907.GD32651@tassilo.jf.intel.com> <20180928212757.GE32651@tassilo.jf.intel.com> Organization: Intel Corp. Message-ID: <22155f49-2f57-73b8-6e89-ddd8a127967b@linux.intel.com> Date: Mon, 1 Oct 2018 09:25:42 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180928212757.GE32651@tassilo.jf.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Jann, > On Fri, Sep 28, 2018 at 11:22:37PM +0200, Jann Horn wrote: >> >> >> Is that true? IIRC if you want to use the perf tools after a kernel >> update, you have to install a new version of perf anyway, no? There are usages in production where perf_event_open() syscall accompanied with read(), mmap() etc. is embedded into application on per-thread basis and is used for self monitoring and dynamic execution tuning. There are also other Perf tools around that, for example, are statically linked and then used as on Linux as on Android. Backward compatibility does matter in these cases. Thanks, Alexey