From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755555Ab3A3U6v (ORCPT ); Wed, 30 Jan 2013 15:58:51 -0500 Received: from one.firstfloor.org ([213.235.205.2]:57516 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751668Ab3A3U6s (ORCPT ); Wed, 30 Jan 2013 15:58:48 -0500 Date: Wed, 30 Jan 2013 21:58:47 +0100 From: Andi Kleen To: Stephane Eranian Cc: Andi Kleen , Ingo Molnar , LKML , Peter Zijlstra , Andrew Morton , Arnaldo Carvalho de Melo , Jiri Olsa , Namhyung Kim , Andi Kleen Subject: Re: [PATCH 07/12] perf, x86: Avoid checkpointed counters causing excessive TSX aborts v3 Message-ID: <20130130205847.GG30577@one.firstfloor.org> References: <1359151245-13179-1-git-send-email-andi@firstfloor.org> <1359151245-13179-8-git-send-email-andi@firstfloor.org> <20130128231659.GW30577@one.firstfloor.org> <20130129010029.GY30577@one.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > That's a very low sampling rate, yet I think it would be rejected by your code. You mean allowed? > But if I come in with frequency 0x7fffffff+1, then that's a very high > frequency, thus > small period, I would pass the test. So I think you need to reinforce the test > for freq=1. I'm aware that there are some configs that can slip through, but there's no other choice if we still allow guest perf stat. The cutoff is somewhat arbitary. It's not a correctness problem, just things can be unexpectedly slower and you may see unexpected NMI messages. -Andi -- ak@linux.intel.com -- Speaking for myself only.