16.04.6 turned out to have 4.15.0-45, which is one of the known-broken releases. Unsurprisingly, it delivered the same poor results as 5.3.
I'm running low on sensible options here. I no longer have the bootable 18.04 stick I used before, but I can create a new one easily enough (as long as I remember to use the .0 image and avoid the HWE stack). But it's not going to tell us anything we don't already know, and it's no use for either normal use or testing. I could wipe the machine and install 18.04, which would cost me years of customisation and bugfixing. Since the bug is in the HWE kernels it would also be possible to test those separately, though it would need a lot of messing around each time. This is sort-of tempting for other reasons anyway, but it'll take weeks of elapsed time to get everything repaired, which is time I won't be able to spend on this bug. I can't really repartition it while doing that, unfortunately. It just has a very small SSD to boot off, and is heavily dependent on the LAN. I could probably JUST about carve out another very small partition to put 18.04 on, which would make the backwards-migration easier and leave me able to validate a fix for this at some point, but it's already seriously hurting for space at times. I'll give it some thought. In the meantime, do you have a preference or any suggestions that might influence that decision? Returning to your original bisection request: since Ubuntu generates its own kernels, if you can give me the mapping from the not-broken 4.15.0-55 to the equivalent starting point in Linus's tree, and likewise for the broken 5.0.0-29, I'll see about sacrificing a USB HDD to that machine for a while for it to build on. No promises, and it'll still take weeks to actually complete, but I'll do what I can. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1847892 Title: large performance regression (~30-40%) in wifi with 19.10 / 5.3 kernel Status in linux package in Ubuntu: Confirmed Bug description: Probably relevant: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1795116 Card is an RTL8723BE. On 16.04 with the HWE stack, after 1795116 was fixed performance was a stable 75-80Mb/s. Linux 4.15.0-55-generic #60~16.04.2-Ubuntu SMP Thu Jul 4 09:03:09 UTC 2019 x86_64 Fri 26-Jul-19 12:28 sent 459,277,171 bytes received 35 bytes 9,278,327.39 bytes/sec Linux 4.15.0-55-generic #60~16.04.2-Ubuntu SMP Thu Jul 4 09:03:09 UTC 2019 x86_64 Sat 27-Jul-19 01:23 sent 459,277,171 bytes received 35 bytes 10,320,836.09 bytes/sec On 18.04, performance was still a stable 75-80Mb/s. After updating to 19.10, performance is typically ~50Mb/s, or about a 37% regression. $ iwconfig wlan0 wlan0 IEEE 802.11 ESSID:"**" Mode:Managed Frequency:2.442 GHz Access Point: 4C:60:DE:FB:A8:AB Bit Rate=150 Mb/s Tx-Power=20 dBm Retry short limit:7 RTS thr=2347 B Fragment thr:off Power Management:on Link Quality=59/70 Signal level=-51 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:315 Missed beacon:0 $ ./wifibench.sh Linux 5.3.0-13-generic #14-Ubuntu SMP Tue Sep 24 02:46:08 UTC 2019 x86_64 Sat 12-Oct-19 20:30 sent 459,277,171 bytes received 35 bytes 5,566,996.44 bytes/sec $ iwconfig wlan0 wlan0 IEEE 802.11 ESSID:"**" Mode:Managed Frequency:2.442 GHz Access Point: 4C:60:DE:FB:A8:AB Bit Rate=150 Mb/s Tx-Power=20 dBm Retry short limit:7 RTS thr=2347 B Fragment thr:off Power Management:on Link Quality=68/70 Signal level=-42 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:315 Missed beacon:0 So no corrupted packets or etc during that transfer. $ ifconfig wlan0 wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.1.33 netmask 255.255.255.0 broadcast 192.168.1.255 ether dc:85:de:e4:17:a3 txqueuelen 1000 (Ethernet) RX packets 56608204 bytes 79066485957 (79.0 GB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 21634510 bytes 8726094217 (8.7 GB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 No issues of any kind in the week that it's been up. Just terrible performance. I'm painfully aware of all the module's parameters etc, and have tried them all, with no change in the results outside of typical wifi variance. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1847892/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
