Re: [net-next PATCH v2 5/8] net: Track start of busy loop instead of when it should end

[Eric Dumazet]

On Thu, 2017-03-23 at 14:37 -0700, Alexander Duyck wrote:
> From: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
> 

> The last bit I changed is to move from using a shift by 10 to just using
> NSEC_PER_USEC and using multiplication for any run time calculations and
> division for a few compile time ones.  This should be more accurate and
> perform about the same on most architectures since modern CPUs typically
> handle multiplication without too much overhead.


busy polling thread can be preempted for more than 2 seconds.

Using usec instead of nanoseconds gave us 3 orders of magnitude cushion.

We do not need nsec accuracy for busy polling users, if this restricts
range and usability under stress.