From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030297AbcGKKdd (ORCPT ); Mon, 11 Jul 2016 06:33:33 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:43960 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758462AbcGKKdb (ORCPT ); Mon, 11 Jul 2016 06:33:31 -0400 Date: Mon, 11 Jul 2016 12:33:28 +0200 From: Peter Zijlstra To: Stephane Eranian Cc: LKML , "ak@linux.intel.com" , Alexander Shishkin , Vince Weaver , Ingo Molnar , Arnaldo Carvalho de Melo , Thomas Gleixner Subject: Re: [RFC] perf: ref-cycle useless with watchdog changes Message-ID: <20160711103328.GI30154@twins.programming.kicks-ass.net> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 10, 2016 at 11:48:11AM -0700, Stephane Eranian wrote: > So we either redirect ref-cycles towards 0x013c > (cpu_clk_unhalted:xlck) or another event maybe Another solution is us introducing (another) fake event, say 0x0400, which will have a constrained mask of: 0x0F | (6 << 32) and varies in actual encoding depending on which counter it lands on. That way we have more flexibility in scheduling the NMI watchdog, and its exact period isn't _that_ important; although we could obviously also fix up some of that if we wanted.