[Bug 1186692] New: CDC ACM speed regression from LEAP 15.2 Kernel 5.3 to KOTD
http://bugzilla.opensuse.org/show_bug.cgi?id=1186692 Bug ID: 1186692 Summary: CDC ACM speed regression from LEAP 15.2 Kernel 5.3 to KOTD Classification: openSUSE Product: openSUSE Distribution Version: Leap 15.2 Hardware: Other OS: Other Status: NEW Severity: Normal Priority: P5 - None Component: Kernel Assignee: kernel-bugs@opensuse.org Reporter: bon@elektron.ikp.physik.tu-darmstadt.de QA Contact: qa-bugs@suse.de Found By: --- Blocker: --- The blackmagic debug probe https://gith.im/blacksphere/blackmagic is a JTAG/SWD debugger that provides GDB server running on a microcontroller, talking to the debug device via JTAG/SWD and exposing the GDB server via a CDC ACM modem implementation. Blackmagic hosted is a PC program that talks to debugger via an additional remote protocol implemented on microcontroller, using the same CDCACM implementation. E.g reading from the device is done in bigger chunks, not single words. Running on KOTD (exactly 5.13.0-rc4-1.g1c805bd-default) read speed dropped about 1/3: Reading flash from 0x08000000 for 1048576 bytes to /tmp/bla Read/Verify succeeded for 1048576 bytes, 52.020 kiB/s while with 5.3 it is above 85 kiB/s or even about 100 kiB/s on a newer USB chipset. strace brings down the speed substantial, so I do not think that is useful for debugging the problem. Hints and help welcome. -- You are receiving this mail because: You are the assignee for the bug.
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--- Comment #1 from Uwe Bonnes
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Uwe Bonnes
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--- Comment #4 from Uwe Bonnes
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--- Comment #6 from Uwe Bonnes
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--- Comment #8 from Takashi Iwai
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--- Comment #9 from Uwe Bonnes
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--- Comment #10 from Takashi Iwai
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--- Comment #11 from Uwe Bonnes
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--- Comment #12 from Uwe Bonnes
uname -a Linux hertz 5.3.0-lp152.78-preempt_custom #3 SMP PREEMPT Thu Jun 17 13:23:44 CEST 2021 x86_64 x86_64 x86_64 GNU/Linux
compiled from https://github.com/SUSE/kernel with " git checkout v5.3" also shows slower speed, on this machine 80 kB/s vs 100 kB/s. -- You are receiving this mail because: You are the assignee for the bug.
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--- Comment #13 from Uwe Bonnes
uname -a Linux hertz 5.13.0-rc6-lp152.78-preempt_custom #4 SMP PREEMPT Thu Jun 17 13:46:19 CEST 2021 x86_64 x86_64 x86_64 GNU/Linux blackmagic -v3 -r /tmp/bla ... Read/Verify succeeded for 65536 bytes, 49.091 kiB/s
This is noticable slower! I will bisect between master and v5.8... -- You are receiving this mail because: You are the assignee for the bug.
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--- Comment #14 from Uwe Bonnes
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