Messages in this thread | | | Subject | Re: setting jiffies as the clocksource stops time | From | Daniel Walker <> | Date | Thu, 17 Jan 2008 14:39:40 -0800 |
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On Thu, 2008-01-17 at 23:34 +0100, Jan Engelhardt wrote: > On Jan 16 2008 13:20, Daniel Walker wrote: > >On Thu, 2008-01-17 at 02:09 +0530, Balaji Rao wrote: > >> Hi, > >> > >> When i set jiffies as the current_clocksource, date(1) tells me > >> that wallclock time has stopped, and soon after that, the system > >> becomes unresponsive. This is not seen with CONFIG_NO_HZ disabled. > >> > >> I wonder how can jiffies be used as a clocksource.. Its value > >> depends on the tick and when we turn off ticks, we would stop > >> incrementing jiffies and when we come come out of idle, we update > >> the jiffies by reading the current_clocksource which now is > >> 'jiffies', and hence jiffies wouldn't get updated. Could this be > >> the explanation ? > > > >Your right, It can't be used as a clocksource with nohz , and the system > >will refuse to automatically switch to it .. > > I think that manually changing to jiffies by echoing into sysfs > should also be prohibited.
Yeah, I wasn't suggesting we shouldn't prevent it .. However, there are tons of way to kill your system by manual changing things ..
Daniel
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