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 <ojaswin@xxxxxxxxxxxxx> > 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. Regard, Ojaswin [1] commit 196e402adf2e4cd66f101923409f1970ec5f1af3 From: Harshad Shirwadkar <harshadshirwadkar@xxxxxxxxx> Date: Thu, 1 Apr 2021 10:21:27 -0700 ext4: improve cr 0 / cr 1 group scanning > > Regards >
