Re: setting jiffies as the clocksource stops time

[Jan Engelhardt]

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.
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