Re: E1000: e1000_update_stats()

[Chris Friesen]

Kok, Auke wrote:

> the update_stats function is only called every two seconds, and scheduled once. I
> think that the chance that two of these functions run in contention in the way you
> point out are practically zero, and if they do then we have much bigger problems
> than just counters being wrong...

I recently did an investigation that ended up sampling a subset of those 
stats every millisecond (to get an accurate picture of how many packets 
were being arriving vs being dropped due to rx_fifo errors over short 
intervals).  Ultimately it turned out that we had very bursty traffic. 
So it's not entirely unheard-of to sample at much higher rates.

At the very least, if we're going to remove the atomicity of reading 
registers and updating stats, how about adding a comment to this effect 
in the code?

Chris
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