From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753803AbbC3ODO (ORCPT ); Mon, 30 Mar 2015 10:03:14 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:33728 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753504AbbC3ODK (ORCPT ); Mon, 30 Mar 2015 10:03:10 -0400 Date: Mon, 30 Mar 2015 16:02:56 +0200 From: Peter Zijlstra To: Kan Liang Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, acme@infradead.org, eranian@google.com, andi@firstfloor.org Subject: Re: [PATCH V5 1/6] perf, x86: use the PEBS auto reload mechanism when possible Message-ID: <20150330140256.GM24151@twins.programming.kicks-ass.net> References: <1424701556-28270-1-git-send-email-kan.liang@intel.com> <1424701556-28270-2-git-send-email-kan.liang@intel.com> <20150330120607.GU23123@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150330120607.GU23123@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 30, 2015 at 02:06:07PM +0200, Peter Zijlstra wrote: > On Mon, Feb 23, 2015 at 09:25:51AM -0500, Kan Liang wrote: > > +++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c > > @@ -673,6 +673,8 @@ void intel_pmu_pebs_enable(struct perf_event *event) > > struct hw_perf_event *hwc = &event->hw; > > > > hwc->config &= ~ARCH_PERFMON_EVENTSEL_INT; > > + if (!event->attr.freq) > > + hwc->flags |= PERF_X86_EVENT_AUTO_RELOAD; > > > > cpuc->pebs_enabled |= 1ULL << hwc->idx; > > Why not in x86_pmu_event_init()? This is not something that will change, > ever, right? intel_pmu_hw_config() would be the better place, as said in a later email.