Kernel PPS processing

[Matthew Selsky]

On Wed, Jun 29, 2016 at 11:48:08AM -0700, Hal Murray wrote:
> > Can you quantify the better?  I would have expected identical...
> 
> Did you look at the graph?
>   http://users.megapathdsl.net/~hmurray/ntpsec/glypnod-pps-kernel.png
> 
> I'm not sure why you would expect performance to be identical.  Dave Mills 
> and crew went to a lot of effort to get code into various kernels, including 
> writing a RFC.  I'd be very surprised if it wasn't a significant improvement.
> 
> The question in my mind is have things changed enough since 1994 so that we 
> can do as well without that code in the kernel?

We tested booting with "nohz=off intel_idle.max_cstate=0" and it made a difference in our production clocks.

I can try to get graphs if needed.


Cheers,
-Matt