Messages in this thread | | | Date | Mon, 21 Mar 2016 17:02:30 -0400 (EDT) | From | Alan Stern <> | Subject | RE: [PATCH] lan78xx: Protect runtime_auto check by #ifdef CONFIG_PM |
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On Mon, 21 Mar 2016 Woojung.Huh@microchip.com 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
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