[openib-general] sysfs exposure of port counters useless?

[Hal Rosenstock]

On Tue, 2006-10-17 at 23:49, Hal Rosenstock wrote:
[snip...]
> > For IB counters in a Cisco switch, we read and reset the 32-bit counters
> > once per second and keep 64-bit counters internally.
> 
> 32 bit byte counters can be pegged in only 16 seconds on a 4x SDR link
> and there are 4x DDR links now (8 seconds) and 12x links (5 seconds) so
> that strategy is inaccurate on busy networks.

I was a little sleepy... I take back the last part of the comment. 1 sec
should be frequent enough. The only issue with this approach is the skew
in the reading of the port counters as the interval is not as precise as
it could be and that is likely to be good enough for these purposes.

-- Hal