On 03/15/2018 11:08 AM, Jakob Unterwurzacher wrote: > On 14.03.18 05:03, John Fastabend wrote: >> On 03/13/2018 11:35 AM, Dave Taht wrote: >>> On Tue, Mar 13, 2018 at 11:24 AM, Jakob Unterwurzacher >>> <jakob.unterwurzac...@theobroma-systems.com> wrote: >>>> During stress-testing our "ucan" USB/CAN adapter SocketCAN driver on Linux >>>> v4.16-rc4-383-ged58d66f60b3 we observed that a small fraction of packets >>>> are >>>> delivered out-of-order. >>>> >> >> Is the stress-testing tool available somewhere? What type of packets >> are being sent? > > > I have reproduced it using two USB network cards connected to each other. The > test tool sends UDP packets containing a counter and listens on the other > interface, it is available at > https://github.com/jakob-tsd/pfifo_stress/blob/master/pfifo_stress.py >
Great thanks, can you also run this with taskset to bind to a single CPU, # taskset 0x1 ./pifof_stress.py And let me know if you still see the OOO. > Here is what I get: > > root@rk3399-q7:~# ./pfifo_stress.py > [...] > expected ctr 0xcdc, received 0xcdd > expected ctr 0xcde, received 0xcdc > expected ctr 0xcdd, received 0xcde > expected ctr 0xe3c, received 0xe3d > expected ctr 0xe3e, received 0xe3c > expected ctr 0xe3d, received 0xe3e > expected ctr 0x1097, received 0x1098 > expected ctr 0x1099, received 0x1097 > expected ctr 0x1098, received 0x1099 > expected ctr 0x17c0, received 0x17c1 > expected ctr 0x17c2, received 0x17c0 > [...] > > Best regards, > Jakob