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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 DF576CA9EAF for ; Thu, 24 Oct 2019 13:56:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B07822166E for ; Thu, 24 Oct 2019 13:56:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="HuuA52as" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393813AbfJXN4g (ORCPT ); Thu, 24 Oct 2019 09:56:36 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:46862 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727811AbfJXN4g (ORCPT ); Thu, 24 Oct 2019 09:56:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=iQ+k/uiUU600gmmhxvDERL2mX3uxFYBS+kLNWX3h6ss=; b=HuuA52asl1NLA1grn9gyUMS2w 61Z7jgUgnCXyjTZF/Gvsxy3TuIQh6N8k8SW9jV32up4gLUp/4sZ/j7T5aG11Mum4hK2SPrx+xX+/H c5Nks8VeUHKB4+Lr00NwYP1yQUC3uqAqnw3ub0KZopHY64CbByprC+EmITLCZEALkNrKhBrGtB9V+ fsQBg5eopG6FImHakzh9Dnja6n1mnD6U20MHxNtpeTqqyqrQtsqTO5o+Z99YQbTaKiIiR8MXh8eCm opMUkfPhHupjJQNpukQ7JL09woWsIFXxEzi63OyEhWrTYZoL3uG3p7SJe62FEDAp3RGe63luyGlWI aEZjp0qtA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1iNdbN-0005Hr-Vf; Thu, 24 Oct 2019 13:56:34 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id CFDB03056C0; Thu, 24 Oct 2019 15:55:33 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 4EA812B1D7CA2; Thu, 24 Oct 2019 15:56:32 +0200 (CEST) Date: Thu, 24 Oct 2019 15:56:32 +0200 From: Peter Zijlstra To: Alexander Shishkin 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 Subject: Re: [PATCH v2 4/4] perf/x86/intel/pt: Opportunistically use single range output mode Message-ID: <20191024135632.GE4114@hirez.programming.kicks-ass.net> References: <20191022095812.67071-1-alexander.shishkin@linux.intel.com> <20191022095812.67071-5-alexander.shishkin@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191022095812.67071-5-alexander.shishkin@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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?