How to Expose Chip-level Ethernet Statistics?

[John Baldwin]

On Saturday, August 04, 2012 3:21:23 pm Tim Kientzle wrote:
> I believe that some of the issues I'm having with this
> Ethernet driver might be easier to diagnose if I could
> expose the chip-level statistics counters (especially queue
> overrun counts).
> 
> Is there a standard way to do this?
> 
> I've looked at systat, netstat, and ifconfig but haven't
> yet found a standard tool that queries this sort of
> information.  (If I could find that, I could figure out
> which ioctl it used…)
> 
> Pointers appreciated…  In particular, if there's another
> Ethernet driver that does this well, I can use that for a
> reference.

Several drivers (igb, em, cxgb, cxgbe, ixgbe, etc.) just expose
a "stats" sysctl node under the device and populate that with
stats.  Typically they install a SYSCTL_PROC() that directly
queries the register.  In some cases they read the registers
via a timer and cache the results and the sysctl handlers returned
the cached results.

-- 
John Baldwin