Messages in this thread | | | Date | Fri, 30 May 2008 15:12:50 -0400 | From | Bill Fink <> | Subject | Re: [PATCH] net: add ability to clear stats via ethtool - e1000/pcnet32 |
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On Thu, 29 May 2008, Alan Cox wrote:
> > > Many of the kernel's accounting accumulators cannot be reset. We > > > handle that in userspace tools by using subtraction. > > > > I don't think that should preclude the ability to reset these, unless it is > > shown that it would break something very badly. > > For one quite a few of the network cards keep the stats in hardware and > don't neccessarily have a way to reset them. In other cases there is a > mix of OS accumulated stats bulk updated by overflow events on the device > itself. > > Its a lot of complexity, and changes all over the places for the sake of > a trivial userspace change. I would suggest you instead write a quick bit > of perl or python that fetches the stats and then updates every second > with the changes.
When diagnosing network problems, the ability to zero counters is a major aid in diagnosis. Writing scripts is not a general solution since often several systems are involved and it's not simple to do this via a script. Saving stats output and running beforeafter on a number of systems is a royal pain when troubleshooting.
I like the idea someone else had. where the clear stats actually did a checkpoint of the stats, and then future get stats would return the diff between the checkpointed and current values (perhaps there could also be a mechanism to still get the absolute values if desired).
-Bill
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