Re: [LUG] Jiffies and the perils of not properly solving a problem properly

[Gordon Henderson <gordon+dcglug@xxxxxxxxxx>]

On Mon, 26 Mar 2012, Simon Waters wrote:

> On 26/03/12 20:48, Gordon Henderson wrote:
> > Isn't it a safety feature - if CONFIG_NO_HZ is set then doesn't jiffies
> > eventually stop?
>
> Who knows? How would you find out?

Really don't know - I rememberd something from the last time, but google 
isn't showing up much.

Hm. few years old:

http://fixunix.com/kernel/329248-setting-jiffies-clocksource-stops-time.html

the only system I have that seems to have jiffies avalable is an ARM 
kernel inside QEMU:

pi@raspberrypi:~$ cat  
/sys/devices/system/clocksource/clocksource0/current_clocksource
timer3
pi@raspberrypi:~$ cat  
/sys/devices/system/clocksource/clocksource0/available_clocksource
timer3 jiffies

I can change it:

root@raspberrypi:/home/pi# cat 
/sys/devices/system/clocksource/clocksource0/current_clocksource
jiffies

and it still seems to run, but maybe that's just QEMU!

Gordon

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