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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 43209C433FE for ; Sat, 12 Feb 2022 07:52:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232546AbiBLHww (ORCPT ); Sat, 12 Feb 2022 02:52:52 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:56316 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229824AbiBLHwv (ORCPT ); Sat, 12 Feb 2022 02:52:51 -0500 Received: from alexa-out-sd-02.qualcomm.com (alexa-out-sd-02.qualcomm.com [199.106.114.39]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C8D626AF3; Fri, 11 Feb 2022 23:52:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1644652368; x=1676188368; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=yxbfpTwDj2fKjhn3UC9YcnQJ7zw3V2Fz0h2ixyRxOPI=; b=saELgblZ4XZLProefbBffMUAh7OdmAnioSu1QFdWveKiXJ6iRO59+2m5 QkW5UnoT3uI2cR3pR0gtISjDL1QTUFfOp01Br6JqTKfHQPEHfOABUz845 LM8xc4qRNSwb9EdkQEqza3TR4/bowoRcY8CG0Mawm621LWBffK/FWicKK w=; Received: from unknown (HELO ironmsg02-sd.qualcomm.com) ([10.53.140.142]) by alexa-out-sd-02.qualcomm.com with ESMTP; 11 Feb 2022 23:52:48 -0800 X-QCInternal: smtphost Received: from nasanex01c.na.qualcomm.com ([10.47.97.222]) by ironmsg02-sd.qualcomm.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Feb 2022 23:52:47 -0800 Received: from nalasex01a.na.qualcomm.com (10.47.209.196) by nasanex01c.na.qualcomm.com (10.47.97.222) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.15; Fri, 11 Feb 2022 23:52:47 -0800 Received: from [10.38.246.233] (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.922.19; Fri, 11 Feb 2022 23:52:44 -0800 Message-ID: Date: Fri, 11 Feb 2022 23:52:41 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.5.1 Subject: Re: [PATCH] devcoredump: increase the device delete timeout to 10 mins Content-Language: en-US To: Greg KH CC: , , , , , , , , , , , , , References: <1644349472-31077-1-git-send-email-quic_abhinavk@quicinc.com> <654d620b-9e14-c47f-b48c-762dc0bd32a1@quicinc.com> From: Abhinav Kumar In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01a.na.qualcomm.com (10.47.209.196) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Greg On 2/11/2022 11:04 PM, Greg KH wrote: > On Fri, Feb 11, 2022 at 10:59:39AM -0800, Abhinav Kumar wrote: >> Hi Greg >> >> Thanks for the response. >> >> On 2/11/2022 3:09 AM, Greg KH wrote: >>> On Tue, Feb 08, 2022 at 11:44:32AM -0800, Abhinav Kumar wrote: >>>> There are cases where depending on the size of the devcoredump and the speed >>>> at which the usermode reads the dump, it can take longer than the current 5 mins >>>> timeout. >>>> >>>> This can lead to incomplete dumps as the device is deleted once the timeout expires. >>>> >>>> One example is below where it took 6 mins for the devcoredump to be completely read. >>>> >>>> 04:22:24.668 23916 23994 I HWDeviceDRM::DumpDebugData: Opening /sys/class/devcoredump/devcd6/data >>>> 04:28:35.377 23916 23994 W HWDeviceDRM::DumpDebugData: Freeing devcoredump node >>> >>> What makes this so slow? Reading from the kernel shouldn't be the >>> limit, is it where the data is being sent to? >> >> We are still checking this. We are seeing better read times when we bump up >> the thread priority of the thread which was reading this. > > Where is the thread sending the data to? The thread is writing the data to a file in local storage. From our profiling, the read is the one taking the time not the write. > >> We are also trying to check if bumping up CPU speed is helping. >> But, results have not been consistently good enough. So we thought we should >> also increase the timeout to be safe. > > Why would 10 minutes be better than 30? What should the limit be? :) Again, this is from our profiling. We are seeing a worst case time of 7 mins to finish the read for our data. Thats where the 10mins came from. Just doubling what we have currently. I am not sure how the current 5 mins timeout came from. > > thanks, > > greg k-h