On Tue, Feb 15, 2011 at 4:13 AM, Johannes Berg
[off-list ref] wrote:

On Mon, 2011-02-14 at 13:58 -0800, Nathaniel Smith wrote:

quoted

I don't know. I take it you're imagining a scheme where mac80211 keeps
a hash table or similar of all packets that have been queued to the
device, and does its own tx rate estimation and calls start/stop_queue
as needed? If that works, then it would be lovely. (Heck, it should
probably go in the generic net layer eventually; ethernet cards have
the same problem.)

Well, no, why would it keep a hash table??

The current patch, whenever it queues a packet, stores
  t = the current time
  S = the current size of the queue
so that later when the TX completes, it can compute (now - t)/S to
estimate the per-packet transmission time. I just mean that you'd need
somewhere to store this stuff, or else find another algorithm for rate
estimation.

-- Nathaniel