Re: [PATCH] mt76: mt7915: add mu-mimo and ofdma debugfs knobs

[Ben Greear <greearb@candelatech.com>]

On 12/6/21 11:25 PM, meichia chiu wrote:
> On Mon, 2021-12-06 at 08:43 -0800, Ben Greear wrote:
>> On 12/6/21 6:10 AM, MeiChia Chiu wrote:
>>> From: MeiChia Chiu <meichia.chiu@mediatek.com>
>>>
>>> Add mu-mimo and ofdma packet counters statistics.
>>
>> Hello,
>>
>> Are these stats clear-on-read in the firmware?  If so, then we need
>> to accumulate
>> them in the driver.
>>
>> Is there any significant downside to enabling the stats?  For
>> instance, a performance
>> degradation in the firmware/hardware?
>>
>> Thanks,
>> Ben
> 
> Hi Ben,
> 
> Yes, the current design is clear-on-read and its sole purpose is for
> debugging only. If you need statistics, this may have to be done in
> another way.

So we could poll these stats in the other logic that polls firmware stats and accumulate
them in the driver and display with debugfs and/or ethtool.  If you don't want
to do the accumulation, and lease add a comment to your patch about the
values being clear-on-read and someone else can add the accumulation logic
later.

> Yes, a performance degradation is expected since enabling this debug
> function would burden MCU with more calculation.

Have you done any testing to verify this?  If it is just bumping a few
counters, it may not matter.  But I don't know how the firmware is actually
implementing this, so maybe it is a lot more expensive than expected?

Thanks,
Ben

> 
> Thanks,
> Meichia
> 


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com