On 23/12/2016 13:44, Felipe Balbi wrote:
Hi,
Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> writes:
Hi,
Jean-Jacques Hiblot <jjhiblot@xxxxxx> writes:
Hi Felipe,
While trying out the v4.9 kernel on a DRA7x, I stumbled upon this
crash. I haven't tried to bisect yet and probably won't be do it
before next year.
This crash doesn't occur with a 4.4 kernel. I suspect it has to do
with the changes in the TRB preparation and interrupt handling.
I don't see the issue if qmult isn't increased. I suspect it's still
there, just harder to reproduce.
can't help you without tracepoints:
# mkdir -p /t
# mount -t tracefs none /t
# cd /t
# echo 81920 > buffer_size_kb
# echo 1 > events/dwc3/enable
(reproduce)
# cp trace ~/trace.txt
send me trace.txt, you probably need to compress it.
nevermind, found it. I just pushed a branch called
dwc3-fix-v4.9-NULL-pointer-deref to my k.org tree. Tested here and I can
still see my 850 MBits/sec with MTU 1500. When setting MTU to 10000,
then I got 1.15 Gbit/sec on iperf.
Let me know your results. I'll send patches out after Xmas.
The results are quite good.
default qmult + MTU 1500 : 430 MBits/s
qmult=20 + MTU 1500 : 500-660 MBits/s. There is a lot of variability
there but it seems to be due to the migration of the iperf process
(using taskset to attach iperf to a specific core helps a lot)
default qmult + MTU 10000 : 2.3 GBits/s. the qmult parameter here has
little effect (+10-20 MBits/s).
Thank you.
Jean-Jacques
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
