Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753849AbaJVP0x (ORCPT ); Wed, 22 Oct 2014 11:26:53 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:41266 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752606AbaJVP0w (ORCPT ); Wed, 22 Oct 2014 11:26:52 -0400 Date: Wed, 22 Oct 2014 17:26:44 +0200 From: Peter Zijlstra To: Alexander Shishkin Cc: Ingo Molnar , linux-kernel@vger.kernel.org, Robert Richter , Frederic Weisbecker , Mike Galbraith , Paul Mackerras , Stephane Eranian , Andi Kleen , kan.liang@intel.com, adrian.hunter@intel.com, acme@infradead.org Subject: Re: [PATCH v5 12/20] x86: perf: intel_pt: Intel PT PMU driver Message-ID: <20141022152644.GZ12706@worktop.programming.kicks-ass.net> References: <1413207948-28202-1-git-send-email-alexander.shishkin@linux.intel.com> <1413207948-28202-13-git-send-email-alexander.shishkin@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1413207948-28202-13-git-send-email-alexander.shishkin@linux.intel.com> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 13, 2014 at 04:45:40PM +0300, Alexander Shishkin wrote: > +static void pt_event_start(struct perf_event *event, int mode) > +{ > + struct pt *pt = this_cpu_ptr(&pt_ctx); > + struct pt_buffer *buf = perf_get_aux(&pt->handle); > + > + if (pt_is_running() || !buf || pt_buffer_is_full(buf, pt) || > + pt_config(event)) { > + event->hw.state = PERF_HES_STOPPED; > + return; > + } > + > + ACCESS_ONCE(pt->handle_nmi) = 1; > + event->hw.state = 0; > + > + pt_config_buffer(buf->cur->table, buf->cur_idx, > + buf->output_off); > + wrmsrl(MSR_IA32_RTIT_STATUS, 0); > + pt_config_start(true); > +} That's two RTIT_CTL writes, should we not try and merge those? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/