From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout.kundenserver.de (mout.kundenserver.de [212.227.17.13]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0BC444C8B for ; Tue, 26 Jul 2022 16:19:58 +0000 (UTC) Received: from [192.168.1.107] ([37.4.248.80]) by mrelayeu.kundenserver.de (mreue106 [212.227.15.183]) with ESMTPSA (Nemesis) id 1N4hBx-1nIvtA3s4l-011jIV; Tue, 26 Jul 2022 17:54:48 +0200 Message-ID: Date: Tue, 26 Jul 2022 17:54:46 +0200 Precedence: bulk X-Mailing-List: regressions@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [Regression] ext4: changes to mb_optimize_scan cause issues on Raspberry Pi Content-Language: en-US To: Ojaswin Mujoo Cc: linux-ext4@vger.kernel.org, Harshad Shirwadkar , Theodore Ts'o , Ritesh Harjani , linux-fsdevel@vger.kernel.org, Linux Kernel Mailing List , Geetika.Moolchandani1@ibm.com, regressions@lists.linux.dev References: <0d81a7c2-46b7-6010-62a4-3e6cfc1628d6@i2se.com> <0840b428-3a77-2339-354f-7fbd3295bb4d@i2se.com> From: Stefan Wahren In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K1:+dY6Kw53OPA/ANxTwrXbadLr9BxDgCp9BdmptMzwrzBDV6TzFUo mkson++S3IEVczYGDV9ClD/8+EP1JZx3x0G/BaBCLVSJrK7U2ORxtS2cqh7iO+DvtEuaJOz hc37biZ6ZyLTX2JQibCW/SJZ65Qg5CWwRjeGwaTua88x8GNXrbQN5d/QU7fruTA9juG7c3a N9k8PSHjlB0rCMUY/CZZA== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1;V03:K0:2LXStBRJMyk=:8b7Jvzhlz0Wac88NY0AcWi ole77AYOknZ9fgYTtVk+nKXozbvgYm8jUZgKSOlcsaDWnsWms2FFupysfgYqh/369P/MsSc77 sYJY6AGESYrcqHFZWx+oUKYm0f1cr3KRK6GxR6UA3qqAj2uZ8ibVjTd4v7SwoTVnzkL8HhRex fb/UX3FxiLouUQeFlP/1srvOMg9+lZz/odOFvrXj29JjECfIjP2Uu2r19QQF7CZtMCep2i5ia puP1cHG0WPveuwQ4otKSyCU0+RI4Gy/683z03hMakckIl/vfZR1n6jwz0cJfEhhLy9jhV9XzI q9WEyZq+k6O09A47kmd+aL+rRGoYOJI7y2ZB49UJvKzdtNTuLv80sdwQJoCB3BB0LhZ6mimlA brvGQxs5ayC9cwHEdpQ6yAyjrqy8lhRENXUScYvV06d1/cEYA10VLEe8+qhK5MNpfyDBOBwvv NEBaz8M1ZqG18xzjO9hZGec4K3NX3Q0vjyJ6H37dOEKSaNZOLmMtfH/gBZcDXTVqf1m4MPSyP 4uL3iJbQYKfaWgwI6dS+jIWfDpEMrV4UiZHWx9FaVNLxrnDWfMQiydaFQX+UANuF9S1AkO2p6 v1ZHfykWkO6wC7bOCVFD3YQ3P/e47IOB7HnakDq1xD+kAt0jWwAaDD+v1fp862/723pNrkfER 8hLDBcaAMdpcAE2DKH0G6865M9KIGVsN/5lUCVby2FLT6DCwEAIhCTUCs9Z1tsw9e40wk+5WJ o5ulyJEBu3vpQ9vwWY/bkITXUN3QWbTLuWQaiosAB8c76bjfXLu8VXmwPT0= Hi Ojaswin, Am 26.07.22 um 08:43 schrieb Ojaswin Mujoo: > On Mon, Jul 25, 2022 at 09:09:32PM +0200, Stefan Wahren wrote: >> Hi Ojaswin, >> >> Am 25.07.22 um 17:07 schrieb Ojaswin Mujoo: >>> On Mon, Jul 18, 2022 at 03:29:47PM +0200, Stefan Wahren wrote: >>>> Hi, >>>> >>>> i noticed that since Linux 5.18 (Linux 5.19-rc6 is still affected) i'm >>>> unable to run "rpi-update" without massive performance regression on my >>>> Raspberry Pi 4 (multi_v7_defconfig + CONFIG_ARM_LPAE). Using Linux 5.17 this >>>> tool successfully downloads the latest firmware (> 100 MB) on my development >>>> micro SD card (Kingston 16 GB Industrial) with a ext4 filesystem within ~ 1 >>>> min. The same scenario on Linux 5.18 shows the following symptoms: >>>> >>>> - download takes endlessly much time and leads to an abort by userspace in >>>> most cases because of the poor performance >>>> - massive system load during download even after download has been aborted >>>> (heartbeat LED goes wild) >>>> - whole system becomes nearly unresponsive >>>> - system load goes back to normal after > 10 min >>>> - dmesg doesn't show anything suspicious >>>> >>>> I was able to bisect this issue: >>>> >>>> ff042f4a9b050895a42cae893cc01fa2ca81b95c good >>>> 4b0986a3613c92f4ec1bdc7f60ec66fea135991f bad >>>> 25fd2d41b505d0640bdfe67aa77c549de2d3c18a bad >>>> b4bc93bd76d4da32600795cd323c971f00a2e788 bad >>>> 3fe2f7446f1e029b220f7f650df6d138f91651f2 bad >>>> b080cee72ef355669cbc52ff55dc513d37433600 good >>>> ad9c6ee642a61adae93dfa35582b5af16dc5173a good >>>> 9b03992f0c88baef524842e411fbdc147780dd5d bad >>>> aab4ed5816acc0af8cce2680880419cd64982b1d good >>>> 14705fda8f6273501930dfe1d679ad4bec209f52 good >>>> 5c93e8ecd5bd3bfdee013b6da0850357eb6ca4d8 good >>>> 8cb5a30372ef5cf2b1d258fce1711d80f834740a bad >>>> 077d0c2c78df6f7260cdd015a991327efa44d8ad bad >>>> cc5095747edfb054ca2068d01af20be3fcc3634f good >>>> 27b38686a3bb601db48901dbc4e2fc5d77ffa2c1 good >>>> >>>> commit 077d0c2c78df6f7260cdd015a991327efa44d8ad >>>> Author: Ojaswin Mujoo >>>> Date:   Tue Mar 8 15:22:01 2022 +0530 >>>> >>>> ext4: make mb_optimize_scan performance mount option work with extents >>>> >>>> If i revert this commit with Linux 5.19-rc6 the performance regression >>>> disappears. >>>> >>>> Please ask if you need more information. >>> Hi Stefan, >>> >>> Apologies, I had missed this email initially. So this particular patch >>> simply changed a typo in an if condition which was preventing the >>> mb_optimize_scan option to be enabled correctly (This feature was >>> introduced in the following commit [1]). I think with the >>> mb_optimize_scan now working, it is somehow causing the firmware >>> download/update to take a longer time. >>> >>> I'll try to investigate this and get back with my findings. >> thanks. I wasn't able to reproduce this heavy load symptoms with every SD >> card. Maybe this depends on the write performance of the SD card to trigger >> the situation (used command to measure write performance: dd if=/dev/zero >> of=/boot/test bs=1M count=30 oflag=dsync,direct ). >> >> I tested a Kingston consumer 32 GB which had nearly constant write >> performance of 13 MB/s and didn't had the heavy load symptoms. The firmware >> update was done in a few seconds, so hard to say that at least the >> performance regression is reproducible. >> >> I also tested 2x Kingston industrial 16 GB which had a floating write >> performance between 5 and 10 MB/s (wear leveling?) and both had the heavy >> load symptoms. >> >> All SD cards has been detected as ultra high speed DDR50 by the emmc2 >> interface. >> >> Best regards >> >>> Regard, >>> Ojaswin >>> >>> [1] >>> commit 196e402adf2e4cd66f101923409f1970ec5f1af3 >>> From: Harshad Shirwadkar >>> Date: Thu, 1 Apr 2021 10:21:27 -0700 >>> >>> ext4: improve cr 0 / cr 1 group scanning >>> >>>> Regards >>>> > Thanks for the info Stefan, I'm still trying to reproduce the issue but > it's slightly challenging since I don't have my RPi handy at the moment. > > In the meantime, would you please try out the mb_optmize_scan=0 command > line options to see if that helps bypass the issue. This will help > confirm if the issue lies in mb_optmize_scan itself or if its something > else. > I run the firmware update 5 times with mb_optimize_scan=0 on my Raspberry Pi 4 and the industrial SD card and everytime the update worked. > > Regards, > Ojaswin