Greg, On Tue, Aug 22, 2017 at 2:25 PM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > USB has always been a big problem with this, the IRQ patch is very long, > and messy and complex. Yeah. > There was an option a while ago to turn USB irqs > into threaded irqs, do those work on your platform? If so, that might > help you out here. Do you mean this: https://lkml.org/lkml/2008/10/20/465 or is there something else/newer? > The usb-serial path should be really "short" overall, compared with the > ohci and tty core logic involved. What USB-serial driver is this that > you are using here? It's the FTDI driver (via generic). I did a quick back-of-the-envelope calculation and it looks like by changing usb/serial/generic.c to move most of the interrupt work to softinterrupt would save about 200 usec out of the 746 usec. Surely that'd be an improvement, but moving the entire OHCI path to softirq would be a much bigger win. --david -- 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
