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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,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 7BF6BC433DB for ; Wed, 13 Jan 2021 09:45:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 22053233F6 for ; Wed, 13 Jan 2021 09:45:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727477AbhAMJoo (ORCPT ); Wed, 13 Jan 2021 04:44:44 -0500 Received: from foss.arm.com ([217.140.110.172]:33268 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727194AbhAMJon (ORCPT ); Wed, 13 Jan 2021 04:44:43 -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 D10BA101E; Wed, 13 Jan 2021 01:43:57 -0800 (PST) Received: from [10.57.56.97] (unknown [10.57.56.97]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9C2723F66E; Wed, 13 Jan 2021 01:43:56 -0800 (PST) Subject: Re: [PATCH V2 08/11] coresight: core: Add support for dedicated percpu sinks To: Anshuman Khandual , linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org Cc: mathieu.poirier@linaro.org, mike.leach@linaro.org, Linu Cherian , linux-kernel@vger.kernel.org References: <1610511498-4058-1-git-send-email-anshuman.khandual@arm.com> <1610511498-4058-9-git-send-email-anshuman.khandual@arm.com> From: Suzuki K Poulose Message-ID: <83939b79-31de-2984-7418-7e4c026dba3a@arm.com> Date: Wed, 13 Jan 2021 09:43:47 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <1610511498-4058-9-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 On 1/13/21 4:18 AM, Anshuman Khandual wrote: > Add support for dedicated sinks that are bound to individual CPUs. (e.g, > TRBE). To allow quicker access to the sink for a given CPU bound source, > keep a percpu array of the sink devices. Also, add support for building > a path to the CPU local sink from the ETM. > > This adds a new percpu sink type CORESIGHT_DEV_SUBTYPE_SINK_PERCPU_SYSMEM. > This new sink type is exclusively available and can only work with percpu > source type device CORESIGHT_DEV_SUBTYPE_SOURCE_PERCPU_PROC. > > This defines a percpu structure that accommodates a single coresight_device > which can be used to store an initialized instance from a sink driver. As > these sinks are exclusively linked and dependent on corresponding percpu > sources devices, they should also be the default sink device during a perf > session. > > Outwards device connections are scanned while establishing paths between a > source and a sink device. But such connections are not present for certain > percpu source and sink devices which are exclusively linked and dependent. > Build the path directly and skip connection scanning for such devices. > > Cc: Mathieu Poirier > Cc: Mike Leach > Cc: Suzuki K Poulose > Signed-off-by: Anshuman Khandual > --- > drivers/hwtracing/coresight/coresight-core.c | 14 ++++++++++++++ > include/linux/coresight.h | 12 ++++++++++++ > 2 files changed, 26 insertions(+) > > diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c > index 0062c89..b300606 100644 > --- a/drivers/hwtracing/coresight/coresight-core.c > +++ b/drivers/hwtracing/coresight/coresight-core.c > @@ -23,6 +23,7 @@ > #include "coresight-priv.h" > > static DEFINE_MUTEX(coresight_mutex); > +DEFINE_PER_CPU(struct coresight_device *, csdev_sink); > > /** > * struct coresight_node - elements of a path, from source to sink > @@ -784,6 +785,13 @@ static int _coresight_build_path(struct coresight_device *csdev, > if (csdev == sink) > goto out; > > + if (coresight_is_percpu_source(csdev) && coresight_is_percpu_sink(sink) && > + sink == per_cpu(csdev_sink, source_ops(csdev)->cpu_id(csdev))) { > + _coresight_build_path(sink, sink, path); > + found = true; > + goto out; > + } > + > /* Not a sink - recursively explore each port found on this element */ > for (i = 0; i < csdev->pdata->nr_outport; i++) { > struct coresight_device *child_dev; > @@ -998,6 +1006,12 @@ coresight_find_default_sink(struct coresight_device *csdev) > { > int depth = 0; > > + if (coresight_is_percpu_source(csdev)) { On a system without per_cpu sink, this would reset the default sink for the source device every single time and fallback to searching every single time. So I think it would be better if did check if the def_sink was not set. We could fold this into the case below may be. i.e, if (!csdev->def_sink) { if (coresight_is_percpu_source(csdev)) csdev->def_sink = per_cpu(csdev_sink, source_ops(csdev)->cpu_id(csdev)); if (!csdev->def_sink) csdev->def_sink = coresight_find_sink(csdev, &depth); } Otherwise looks good to me. Suzuki 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=-15.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 2D4F3C433DB for ; Wed, 13 Jan 2021 09:45:30 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AF964233F6 for ; Wed, 13 Jan 2021 09:45:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AF964233F6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=jNtulyrKQBo3CayPCeESZOdMIuV+zsFE1Kix3+DrDlQ=; b=INf99ikAVsAgBJRzNiKbf11OM UbpL+M+geebOXdAgU9LCcdodoWYDIVZL3+Cgx6lI6zq6h5All99teeI7+1Gfljw41oXb1QRcCv233 jQTX9jyiQPxfsfvGmGKTlHFzNP4Zi2ZnCc/h16u5HnIRFm9j9wta+UZeI+XrZLzWmyRMxH1UvUpQq Igg0Szi1+BwwZWnmuYKDJpN2xKNIFsf79SkhIp4OnlXUgWOF9bPv7YXdr7FwrZXtgL+zHPrsxfvtE cUfCnQZFQ/nnOZVInnTDx8ADtzYB9CAyv4Cp71z26zirM03BfUdAX+HqSZJXqx66ROnLKqzvnTe/V +YhrVZsJw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kzch7-0007lE-AW; Wed, 13 Jan 2021 09:44:01 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kzch5-0007jo-1U for linux-arm-kernel@lists.infradead.org; Wed, 13 Jan 2021 09:44:00 +0000 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 D10BA101E; Wed, 13 Jan 2021 01:43:57 -0800 (PST) Received: from [10.57.56.97] (unknown [10.57.56.97]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9C2723F66E; Wed, 13 Jan 2021 01:43:56 -0800 (PST) Subject: Re: [PATCH V2 08/11] coresight: core: Add support for dedicated percpu sinks To: Anshuman Khandual , linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org References: <1610511498-4058-1-git-send-email-anshuman.khandual@arm.com> <1610511498-4058-9-git-send-email-anshuman.khandual@arm.com> From: Suzuki K Poulose Message-ID: <83939b79-31de-2984-7418-7e4c026dba3a@arm.com> Date: Wed, 13 Jan 2021 09:43:47 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <1610511498-4058-9-git-send-email-anshuman.khandual@arm.com> Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210113_044359_242190_AF46F375 X-CRM114-Status: GOOD ( 29.34 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, Linu Cherian , mathieu.poirier@linaro.org, mike.leach@linaro.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 1/13/21 4:18 AM, Anshuman Khandual wrote: > Add support for dedicated sinks that are bound to individual CPUs. (e.g, > TRBE). To allow quicker access to the sink for a given CPU bound source, > keep a percpu array of the sink devices. Also, add support for building > a path to the CPU local sink from the ETM. > > This adds a new percpu sink type CORESIGHT_DEV_SUBTYPE_SINK_PERCPU_SYSMEM. > This new sink type is exclusively available and can only work with percpu > source type device CORESIGHT_DEV_SUBTYPE_SOURCE_PERCPU_PROC. > > This defines a percpu structure that accommodates a single coresight_device > which can be used to store an initialized instance from a sink driver. As > these sinks are exclusively linked and dependent on corresponding percpu > sources devices, they should also be the default sink device during a perf > session. > > Outwards device connections are scanned while establishing paths between a > source and a sink device. But such connections are not present for certain > percpu source and sink devices which are exclusively linked and dependent. > Build the path directly and skip connection scanning for such devices. > > Cc: Mathieu Poirier > Cc: Mike Leach > Cc: Suzuki K Poulose > Signed-off-by: Anshuman Khandual > --- > drivers/hwtracing/coresight/coresight-core.c | 14 ++++++++++++++ > include/linux/coresight.h | 12 ++++++++++++ > 2 files changed, 26 insertions(+) > > diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c > index 0062c89..b300606 100644 > --- a/drivers/hwtracing/coresight/coresight-core.c > +++ b/drivers/hwtracing/coresight/coresight-core.c > @@ -23,6 +23,7 @@ > #include "coresight-priv.h" > > static DEFINE_MUTEX(coresight_mutex); > +DEFINE_PER_CPU(struct coresight_device *, csdev_sink); > > /** > * struct coresight_node - elements of a path, from source to sink > @@ -784,6 +785,13 @@ static int _coresight_build_path(struct coresight_device *csdev, > if (csdev == sink) > goto out; > > + if (coresight_is_percpu_source(csdev) && coresight_is_percpu_sink(sink) && > + sink == per_cpu(csdev_sink, source_ops(csdev)->cpu_id(csdev))) { > + _coresight_build_path(sink, sink, path); > + found = true; > + goto out; > + } > + > /* Not a sink - recursively explore each port found on this element */ > for (i = 0; i < csdev->pdata->nr_outport; i++) { > struct coresight_device *child_dev; > @@ -998,6 +1006,12 @@ coresight_find_default_sink(struct coresight_device *csdev) > { > int depth = 0; > > + if (coresight_is_percpu_source(csdev)) { On a system without per_cpu sink, this would reset the default sink for the source device every single time and fallback to searching every single time. So I think it would be better if did check if the def_sink was not set. We could fold this into the case below may be. i.e, if (!csdev->def_sink) { if (coresight_is_percpu_source(csdev)) csdev->def_sink = per_cpu(csdev_sink, source_ops(csdev)->cpu_id(csdev)); if (!csdev->def_sink) csdev->def_sink = coresight_find_sink(csdev, &depth); } Otherwise looks good to me. Suzuki _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel