Re: [BUG nohz]: wrong user and system time accounting

Thomas Gleixner
2017-04-12T14:58:06Z

On Wed, 12 Apr 2017, Frederic Weisbecker wrote:
> On Tue, Apr 11, 2017 at 04:22:48PM +0200, Thomas Gleixner wrote:
> > It's not different from the current jiffies based stuff at all. Same
> > failure mode.
>
> Yes you're right, I got confused again. So to fix this we could do our snapshots
> at a frequency lower than HZ but still high enough to avoid overhead.
>
> Something like TICK_NSEC / 2 ?

If you are using TSC anyway then you can do proper accumulation for both
system and user and only account the data when the accumulation is more
than a jiffie.

Thanks,

tglx