From patchwork Tue Sep 14 10:26:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suzuki K Poulose X-Patchwork-Id: 12492725 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=-17.1 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,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 A1D4EC433F5 for ; Tue, 14 Sep 2021 10:31:27 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 739A160F21 for ; Tue, 14 Sep 2021 10:31:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 739A160F21 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=EUAaAbCOr0X4NY5r1dJH0L7WeBEjVB4q/YNPQ59826E=; b=hwhqdoOHiYN/Er +gXqFL9i6zDP3pY4tdRZTe0ayVhQ0sWKzONjT4xxOJDmOJ6v5lOe6z+NiJH7w0q1j7yQMFR/iQzpj r2gR00Cb9kWvSYyoQJw/OMqIaPjKtRULn4AWrRN0EKsUg8jZggxYK9TgaalpzCoh9cJWFbBWp0lsP hO2jrRplwYvxvVPUgafwczsO/FR1JVvraxIJW0INr2Z9joqqlLdqazLNuIYVojkG6z3ylfZOzt2Ox Xqf7yROlkfidyhyJD7O+TtDdUwxAs7nYRzTgrIr6t1SNQDlvIfiV8AZTV4SyPNSGXiLDiZ3fK5RKf q5XrCx0IxfNtG4IkyNwg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mQ5gU-005DcO-Ux; Tue, 14 Sep 2021 10:29:03 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mQ5f6-005D4m-Vy for linux-arm-kernel@lists.infradead.org; Tue, 14 Sep 2021 10:27:38 +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 7590C101E; Tue, 14 Sep 2021 03:27:35 -0700 (PDT) Received: from ewhatever.cambridge.arm.com (ewhatever.cambridge.arm.com [10.1.197.1]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id CB08B3F59C; Tue, 14 Sep 2021 03:27:33 -0700 (PDT) From: Suzuki K Poulose To: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org, mathieu.poirier@linaro.org, anshuman.khandual@arm.com, mike.leach@linaro.org, leo.yan@linaro.org, tamas.zsoldos@arm.com, jinlmao@qti.qualcomm.com, al.grant@arm.com, denik@google.com, Suzuki K Poulose , James Clark Subject: [PATCH v3 07/10] coresight: trbe: Do not truncate buffer on IRQ Date: Tue, 14 Sep 2021 11:26:38 +0100 Message-Id: <20210914102641.1852544-8-suzuki.poulose@arm.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20210914102641.1852544-1-suzuki.poulose@arm.com> References: <20210914102641.1852544-1-suzuki.poulose@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210914_032737_096847_5CCCD4F1 X-CRM114-Status: GOOD ( 16.10 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The TRBE driver marks the AUX buffer as TRUNCATED when we get an IRQ on FILL event. This has rather unwanted side-effect of the event being disabled when there may be more space in the ring buffer. So, instead of TRUNCATE we need a different flag to indicate that the trace may have lost a few bytes (i.e from the point of generating the FILL event until the IRQ is consumed). Anyways, the userspace must use the size from RECORD_AUX headers to restrict the "trace" decoding. Using PARTIAL flag causes the perf tool to generate the following warning: Warning: AUX data had gaps in it XX times out of YY! Are you running a KVM guest in the background? which is pointlessly scary for a user. The other remaining options are : - COLLISION - Use by SPE to indicate samples collided - Add a new flag - Specifically for CoreSight, doesn't sound so good, if we can re-use something. Given that we don't already use the "COLLISION" flag, the above behavior can be notified using this flag for CoreSight. Cc: Mathieu Poirier Cc: James Clark Cc: Mike Leach Cc: Anshuman Khandual Cc: Leo Yan Signed-off-by: Suzuki K Poulose Reviewed-by: Anshuman Khandual --- Changes since v2: - The perf tool patch for reporting collisions is queued. --- drivers/hwtracing/coresight/coresight-trbe.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c index de99dd0aecd3..a1a15fa6c4ae 100644 --- a/drivers/hwtracing/coresight/coresight-trbe.c +++ b/drivers/hwtracing/coresight/coresight-trbe.c @@ -612,7 +612,7 @@ static unsigned long arm_trbe_update_buffer(struct coresight_device *csdev, * for correct size. Also, mark the buffer truncated. */ write = get_trbe_limit_pointer(); - perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED); + perf_aux_output_flag(handle, PERF_AUX_FLAG_COLLISION); } offset = write - base; @@ -705,7 +705,7 @@ static void trbe_handle_overflow(struct perf_output_handle *handle) * Mark the buffer as truncated, as we have stopped the trace * collection upon the WRAP event, without stopping the source. */ - perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED); + perf_aux_output_flag(handle, PERF_AUX_FLAG_COLLISION); perf_aux_output_end(handle, size); event_data = perf_aux_output_begin(handle, event); if (!event_data) {