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=-17.3 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=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 C6AABC433F5 for ; Wed, 15 Sep 2021 06:45:43 +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 94DAC61029 for ; Wed, 15 Sep 2021 06:45:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 94DAC61029 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:In-Reply-To:MIME-Version:Date: Message-ID:From:References:Cc:To:Subject:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=5jc70nOq3urKsgh3OL3maRezlgKA2NRf1ukJLhxycBI=; b=U8E/mwkFJ4+w5npCjFa5ujw7TJ S4ld5iQPTyySa861Xh849udTKOn9YU2sKy0pNQHY59y5CCJ4NENq2WyFN/osjwBKPVuNV65XuG+HJ uu3t+tAFFEWShU47NFSjAku09DZBktCTM3vCaUF+sAheF5VT9gy5f2pXpJIv+/rH7XvtEjYeRy3Bt h3EuvMfDRM3r/Xwp3NUTId0RIfTSTVj2D7DEE3G5AtEA7pYKNjkQRb5nNPa3dlkCK/yrhLl9rsYZZ qZoajEJboJPZQJXrVOOMFEW8hxRnej+YpuHm2rHGBz5eQqla+O8/URd2cGQZn0fvVpVPnXeorWySx wKY0mV1w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mQOdw-008E73-G9; Wed, 15 Sep 2021 06:43:40 +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 1mQOds-008E6O-Hb for linux-arm-kernel@lists.infradead.org; Wed, 15 Sep 2021 06:43:38 +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 1A43831B; Tue, 14 Sep 2021 23:43:33 -0700 (PDT) Received: from [10.163.70.189] (unknown [10.163.70.189]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 91FB93F719; Tue, 14 Sep 2021 23:43:29 -0700 (PDT) Subject: Re: [PATCH v3 07/10] coresight: trbe: Do not truncate buffer on IRQ To: Suzuki K Poulose , coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org, mathieu.poirier@linaro.org, mike.leach@linaro.org, leo.yan@linaro.org, tamas.zsoldos@arm.com, jinlmao@qti.qualcomm.com, al.grant@arm.com, denik@google.com, James Clark References: <20210914102641.1852544-1-suzuki.poulose@arm.com> <20210914102641.1852544-8-suzuki.poulose@arm.com> From: Anshuman Khandual Message-ID: <93fe346a-156a-4b23-6e8e-14adfcd54fd4@arm.com> Date: Wed, 15 Sep 2021 12:14:34 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210914102641.1852544-8-suzuki.poulose@arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210914_234336_734120_94B6F94A X-CRM114-Status: GOOD ( 28.43 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 9/14/21 3:56 PM, Suzuki K Poulose wrote: > 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) { > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel