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. > > What do you mean statistics interval? > Interval calling ndo_get_stats64 or another thread/timer or else getting statistics? The time between calls to ndo_get_stats64, since that's the routine which queries the device. 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
