From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C420BCA9EA0 for ; Fri, 25 Oct 2019 12:19:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A37A221D71 for ; Fri, 25 Oct 2019 12:19:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2440196AbfJYMTm (ORCPT ); Fri, 25 Oct 2019 08:19:42 -0400 Received: from mga12.intel.com ([192.55.52.136]:49239 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726484AbfJYMTm (ORCPT ); Fri, 25 Oct 2019 08:19:42 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Oct 2019 05:19:41 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,228,1569308400"; d="scan'208";a="201794460" Received: from um.fi.intel.com (HELO um) ([10.237.72.57]) by orsmga003.jf.intel.com with ESMTP; 25 Oct 2019 05:19:39 -0700 From: Alexander Shishkin To: Peter Zijlstra Cc: Arnaldo Carvalho de Melo , Ingo Molnar , linux-kernel@vger.kernel.org, jolsa@redhat.com, adrian.hunter@intel.com, mathieu.poirier@linaro.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com Subject: Re: [PATCH v2 4/4] perf/x86/intel/pt: Opportunistically use single range output mode In-Reply-To: <20191024135632.GE4114@hirez.programming.kicks-ass.net> References: <20191022095812.67071-1-alexander.shishkin@linux.intel.com> <20191022095812.67071-5-alexander.shishkin@linux.intel.com> <20191024135632.GE4114@hirez.programming.kicks-ass.net> Date: Fri, 25 Oct 2019 15:19:38 +0300 Message-ID: <87blu5ggpx.fsf@ashishki-desk.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Peter Zijlstra writes: > On Tue, Oct 22, 2019 at 12:58:12PM +0300, Alexander Shishkin wrote: >> Most of PT implementations support Single Range Output mode, which is >> an alternative to ToPA that can be used for a single contiguous buffer >> and if we don't require an interrupt, that is, in AUX snapshot mode. >> >> Now that perf core will use high order allocations for the AUX buffer, >> in many cases the first condition will also be satisfied. >> >> The two most obvious benefits of the Single Range Output mode over the >> ToPA are: >> * not having to allocate the ToPA table(s), >> * not using the ToPA walk hardware. >> >> Make use of this functionality where available and appropriate. > > This seems independent of the snapshot stuff, right? Yes, it depends on the previous PT driver patch for context, though. I'll drop it from the set. Regards, -- Alex