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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 5C117C31E44 for ; Wed, 12 Jun 2019 02:38:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2C160207E0 for ; Wed, 12 Jun 2019 02:38:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2408470AbfFLCiu (ORCPT ); Tue, 11 Jun 2019 22:38:50 -0400 Received: from mga18.intel.com ([134.134.136.126]:52684 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406202AbfFLCiu (ORCPT ); Tue, 11 Jun 2019 22:38:50 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 11 Jun 2019 19:38:48 -0700 X-ExtLoop1: 1 Received: from allen-box.sh.intel.com (HELO [10.239.159.136]) ([10.239.159.136]) by orsmga004.jf.intel.com with ESMTP; 11 Jun 2019 19:38:43 -0700 Cc: baolu.lu@linux.intel.com, David Woodhouse , Joerg Roedel , Bjorn Helgaas , Christoph Hellwig , ashok.raj@intel.com, jacob.jun.pan@intel.com, alan.cox@intel.com, kevin.tian@intel.com, mika.westerberg@linux.intel.com, Ingo Molnar , Greg Kroah-Hartman , pengfei.xu@intel.com, Marek Szyprowski , Robin Murphy , Jonathan Corbet , Boris Ostrovsky , Juergen Gross , Stefano Stabellini , Steven Rostedt , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Jacob Pan Subject: Re: [PATCH v4 7/9] iommu/vt-d: Add trace events for domain map/unmap To: Konrad Rzeszutek Wilk References: <20190603011620.31999-1-baolu.lu@linux.intel.com> <20190603011620.31999-8-baolu.lu@linux.intel.com> <20190610160838.GY28796@char.us.oracle.com> From: Lu Baolu Message-ID: <297f6aaa-36c0-bae3-fa36-7ca544dc5f35@linux.intel.com> Date: Wed, 12 Jun 2019 10:31:34 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190610160838.GY28796@char.us.oracle.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 6/11/19 12:08 AM, Konrad Rzeszutek Wilk wrote: > On Mon, Jun 03, 2019 at 09:16:18AM +0800, Lu Baolu wrote: >> This adds trace support for the Intel IOMMU driver. It >> also declares some events which could be used to trace >> the events when an IOVA is being mapped or unmapped in >> a domain. > > Is that even needed considering SWIOTLB also has tracing events? > Currently there isn't any trace point in swiotlb_tbl_map_single(). If we want to add trace point there, I hope we can distinguish the bounce page events from other use cases (such as bounce buffer for direct dma), so that we could calculate how many percents of DMA buffers used by a specific device driver needs to use bounce page. Best regards, Baolu