On Mon, 21 Mar 2016 Woojung.Huh@xxxxxxxxxxxxx wrote: > > But this leaves open the issue that querying the device too often will > > prevent it from going into autosuspend. It seems to me that the best > > way to deal with this is to make sure that the autosuspend timeout is > > shorter than the interal between queries, not to make the querying > > conditional on !runtime_auto. > > Short autosuspend timeout can affect performance. For instance our experiments showed that > shorter than 10sec timeout made Ethernet performance degrade because of wakeup delays. > So, just putting shorter timeout may have some side effects. Sure. This just means that you need a long statistics interval -- longer than the autosuspend timeout. That's why I suggested making the interval adjustable. Alternatively, you could automatically set the statistics interval to the autosuspend timeout (or 0 if autosuspend is disabled) plus some fixed value. Alan Stern -- 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
