From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966523AbdACWGn (ORCPT ); Tue, 3 Jan 2017 17:06:43 -0500 Received: from smtpauth03.mfg.siteprotect.com ([64.26.60.145]:50438 "EHLO smtpauth03.mfg.siteprotect.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752790AbdACWGk (ORCPT ); Tue, 3 Jan 2017 17:06:40 -0500 Date: Tue, 3 Jan 2017 17:06:41 -0500 (EST) From: Vince Weaver X-X-Sender: vince@pianoman.cluster.toy To: Jiri Olsa cc: Peter Zijlstra , Jiri Olsa , lkml , Ingo Molnar , Andi Kleen , Alexander Shishkin , Arnaldo Carvalho de Melo Subject: Re: [PATCH] perf/x86: Reject non sampling events with precise_ip In-Reply-To: <20170103142454.GA26251@krava> Message-ID: References: <1482931866-6018-1-git-send-email-jolsa@kernel.org> <1482931866-6018-3-git-send-email-jolsa@kernel.org> <20170103094059.GC3093@worktop> <20170103142454.GA26251@krava> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 3 Jan 2017, Jiri Olsa wrote: > On Tue, Jan 03, 2017 at 10:40:59AM +0100, Peter Zijlstra wrote: > > > > I think we should reject non sampling pebs events, as you say they make > > no sense what so ever. > > ook, attached > you can use the PEBS events to gather aggregate stats though and they seem roughly right. Are they truly meaningless? I had misremembered that they might not have the determinism problems of regular events (turns out that's wrong). They oddly seem to be worse in some limited tests I did. So I guess nothing will be lost if they're disabled. Vince