Re: [PATCH 1/3] cfg80211: add get_max_tp() API

[Antonio Quartulli <antonio@open-mesh.com>]

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Hi all,

On Fri, Apr 05, 2013 at 06:20:01AM -0700, Johannes Berg wrote:
> On Fri, 2013-04-05 at 10:39 +0200, Antonio Quartulli wrote:
> 
> > In the batman-adv module (which implements a routing protocol for mesh networks
> > on layer 2) we are trying to switch metric from packet loss to throughput and
> > the idea is to read the estimation from the rate control component (thanks to
> > the API mechanism in cfg/mac80211 this can be eventually changed later).
> 
> While this makes some sense, going into the details of your patchset I
> find that it's overly complex.
> 
> I think you should fix minstrel to report the best rate in
> txrc.reported_rate. This would also have the effect of not showing
> sampling attempts to userspace in the "current TX rate", which generally
> makes a lot of sense.

But the reported_rate field would just contain the index of the selected rate,
not the throughput. As far as I can tell the latter is an RC private information
(it not exported anywhere outside of the RC algorithm) and that is why I made
this API which would directly talk to minstrel and get this value.

> 
> After doing that, reading the rate becomes a get_station_info() call or
> so.
> 

true, but still we have the problem above..unless I alter the ieee8011_tx_rate
and rate_info struct..but I don't know if this would make much sense.

> One more detail:
> 
> int cfg80211_get_max_tp(struct wireless_dev *wdev, u8 *peer, u32 *tp)
> 
> I really don't think that the wireless_dev should be necessary for this,
> it ought to be just a netdev IMHO.

well, yes, I can pass the struct net_dev only, even if I need the wdev to obtain
the cf80211_register_dev object for the ops.

> Also, the peer should be const :)

Right


Thanks.
Cheer,


-- 
Antonio Quartulli

..each of us alone is worth nothing..
Ernesto "Che" Guevara

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