Re: [PATCH v7 3/3] nl80211/mac80211: Report signal average

[Bob Copeland]

On Wed, Nov 17, 2010 at 11:16 AM, Johannes Berg
<johannes@xxxxxxxxxxxxxxxx> wrote:
> On Wed, 2010-11-17 at 17:28 +0900, Bruno Randolf wrote:
>> I understand that this could be more efficient, but if it matters or not -
>> honestly, I don't know. Can a more knowledgeable person than me comment on
>> this?
>
> Yes, it does matter -- think of an embedded MIPS board running at 500MHz
> and trying to push 11n speeds.

I assume the number of samples (weight) is the more
important tunable.  One option is you can require factor
to be a power of two that is much larger than weight,
then at least you can store factor/weight precomputed
and multiply by it instead of doing a divide in ewma_add.
Then ewma_get can also just be a shift as well.

-- 
Bob Copeland %% www.bobcopeland.com
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/