With the ongoing work to add BQL to Socket CAN, I figured out that it would be nice to have an easy way to mesure the latency. And one easy way to do so it to check the round trip time of the packet by doing the difference between the software rx timestamp and the software tx timestamp. rx timestamps are already available. This patch gives the missing piece: add a tx software timestamp feature to the CAN devices. Of course, the tx software timestamp might also be used for other purposes such as performance measurements of the different queuing disciplines (e.g. by checking the difference between the kernel tx software timestamp and the userland tx software timestamp). v2 was a mistake, please ignore it (fogot to do git add, changes were not reflected...) v3 reflects the comments that Jeroen made in https://lkml.org/lkml/2021/1/10/54 v4 rebases the patch on linux-can-next/testing and suppress the comment related to SOF_TIMESTAMPING_TX_HARDWARE. Reference: https://lore.kernel.org/linux-can/20210111171152.GB11715@xxxxxxxxxxxxxxxxxx/ Vincent Mailhol (1): can: dev: add software tx timestamps drivers/net/can/dev/skb.c | 2 ++ 1 file changed, 2 insertions(+) -- 2.26.2
