Reporting firmware stats to ethtool

[Dave Taht]

On Fri, Aug 8, 2014 at 8:42 AM, Ben Greear <greearb at candelatech.com> wrote:
> On 08/08/2014 02:06 AM, Kalle Valo wrote:
>> Ben Greear <greearb at candelatech.com> writes:
>>
>>> I'm working on a patch to report the stats seen in debugfs/...ath10k/fw_stats
>>> as ethtool stats, somewhat similar to how ath9k does it.
>>>
>>> I notice that my user-space tool is reporting huge numbers because
>>> the stats are reset to zero when firmware restarts, and so my tool
>>> thinks the stats wrapped.
>>>
>>> I can fix my tool easily enough, but I first wanted to see if
>>> anyone had strong feelings about keeping the stats from resetting
>>> to zero by storing history and calculating diffs in the driver.
>>>
>>> I think my preference is to punt this to user-space, but if
>>> someone feels otherwise, please let me know sooner than later.
>>
>> I also prefer to have this in user space, but how does user space know
>> when the stats have been zeroed?
>
> Poll often enough that it cannot increment more than 2 billion (or other large number)
> between polls, and then if polled value is less than previous (and difference is > 2 billion),
> we know we had a reset and not a wrap.

I do kind of prefer 64 bit counters in the general case. Nuke it from
orbit, it's the only way to be sure.

> User-space stats will not be perfect in the case of firmware resets, or resets
> after the 'large number', but nothing is going to make it perfect, and in
> practice, this seems good enough.
>
> Thanks,
> Ben
>
> --
> Ben Greear <greearb at candelatech.com>
> Candela Technologies Inc  http://www.candelatech.com
>
>
> _______________________________________________
> ath10k mailing list
> ath10k at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/ath10k



-- 
Dave Täht

NSFW: https://w2.eff.org/Censorship/Internet_censorship_bills/russell_0296_indecent.article