On Mon, Apr 22, 2013 at 12:50:34AM +0000, Pan, Zhenjie wrote: > > I believe it mattered to the Chrome folks. They want the watchdog to be as > > tight as possible so the user experience isn't a hang but a quick reboot > > instead. They like setting the watchdog to something like 2 seconds. > > > > There was a patch a few months ago that tried to hack around this issue and > > I > > suggested this approach as a better solution. I forgot what the original > > problem was. Perhaps someone can jump in and explain the problem being > > solved (other than the watchdog isn't always 10 seconds)? > > > > Cheers, > > Don > > Yes, I also think the period is important sometimes. > As I mentioned before, the case I meet is: > When the system hang with interrupt disabled, we use NMI to detect. > Then it will find hard lockup and cause a panic. > Panic is very important for debug these kind of issues. > > But if cpu frequency change, the period will be 2 times, 3 times even > more.(if cpu can down from 2.0GHz to 200MHz, will be 10 times, it's a very > big deviation) > This make watchdog reset happen before hard lockup detect.
So you are saying with the longer hard lockup delay, the iTCO_wdt is firing before the hard lockup detector? Cheers, Don -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
