From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lin Ming Subject: Re: What perf_event_paranoid can do? Date: Mon, 21 Mar 2011 16:35:11 +0800 Message-ID: References: <20110321061435.GA52815@cs.nctu.edu.tw> Mime-Version: 1.0 Content-Type: text/plain; charset=Big5 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-iw0-f174.google.com ([209.85.214.174]:57806 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751435Ab1CUIfL convert rfc822-to-8bit (ORCPT ); Mon, 21 Mar 2011 04:35:11 -0400 Received: by iwn34 with SMTP id 34so6160558iwn.19 for ; Mon, 21 Mar 2011 01:35:11 -0700 (PDT) In-Reply-To: <20110321061435.GA52815@cs.nctu.edu.tw> Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: linux-perf-users@vger.kernel.org Cc: =?UTF-8?B?6Zmz6Z+L5Lu7?= On Mon, Mar 21, 2011 at 2:14 PM, =B3=AF=AD=B3=A5=F4 wrote: > Hi, folks > > I don't know what "perf_event_paranoid" is for. Sometimes > `perf` told me tweaking perf_event_paranoid. For example, > > $ perf stat -e branches:pp ls > No permission to collect stats. > Consider tweaking /proc/sys/kernel/perf_event_paranoid. > > I cannot find any document talks about what perf_event_paranoid > is and what we can do on it. It's used to control if some action is allowed or not for normal user. See comments at kernel/perf_event.c: /* * perf event paranoia level: * -1 - not paranoid at all * 0 - disallow raw tracepoint access for unpriv * 1 - disallow cpu events for unpriv * 2 - disallow kernel profiling for unpriv */ Lin Ming > > Any suggestion appreciated. > > Regards, > chenwj > > -- > Wei-Ren Chen (=B3=AF=AD=B3=A5=F4) > Parallel Processing Lab, Institute of Information Science, > Academia Sinica, Taiwan (R.O.C.) > Tel:886-2-2788-3799 #1667 > -- > To unsubscribe from this list: send the line "unsubscribe linux-perf-= users" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >