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=-8.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 7AA05C2D0A3 for ; Thu, 12 Nov 2020 09:31:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 20AB021D40 for ; Thu, 12 Nov 2020 09:31:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726925AbgKLJb1 (ORCPT ); Thu, 12 Nov 2020 04:31:27 -0500 Received: from foss.arm.com ([217.140.110.172]:45154 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725928AbgKLJb0 (ORCPT ); Thu, 12 Nov 2020 04:31:26 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1909B139F; Thu, 12 Nov 2020 01:31:26 -0800 (PST) Received: from [10.57.23.123] (unknown [10.57.23.123]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 21CE13F73C; Thu, 12 Nov 2020 01:31:23 -0800 (PST) Subject: Re: [RFC 10/11] coresgith: etm-perf: Connect TRBE sink with ETE source To: Anshuman Khandual , linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org Cc: linux-kernel@vger.kernel.org, mathieu.poirier@linaro.org, mike.leach@linaro.org References: <1605012309-24812-1-git-send-email-anshuman.khandual@arm.com> <1605012309-24812-11-git-send-email-anshuman.khandual@arm.com> From: Suzuki K Poulose Message-ID: Date: Thu, 12 Nov 2020 09:31:17 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.1 MIME-Version: 1.0 In-Reply-To: <1605012309-24812-11-git-send-email-anshuman.khandual@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Anshuman, On 11/10/20 12:45 PM, Anshuman Khandual wrote: > Unlike traditional sink devices, individual TRBE instances are not detected > via DT or ACPI nodes. Instead TRBE instances are detected during CPU online > process. Hence a path connecting ETE and TRBE on a given CPU would not have > been established until then. This adds two coresight helpers that will help > modify outward connections from a source device to establish and terminate > path to a given sink device. But this method might not be optimal and would > be reworked later. > > Signed-off-by: Anshuman Khandual Instead of this, could we come up something like a percpu_sink concept ? That way, the TRBE driver could register the percpu_sink for the corresponding CPU and we don't have to worry about the order in which the ETE will be probed on a hotplugged CPU. (i.e, if the TRBE is probed before the ETE, the following approach would fail to register the sink). And the default sink can be initialized when the ETE instance first starts looking for it. Suzuki