On 2018-10-11 03:38, Toke Høiland-Jørgensen wrote:
Rajkumar Manoharan <rmanohar@xxxxxxxxxxxxxx> writes:
Hmm... mine is bit different. txqs are refilled only once for all
txqs.
It will give more opportunity for non-served txqs. drv_wake_tx_queue
won't be
called from may_tx as the driver anyway will not push packets in
pull-mode.
So, as far as I can tell, this requires the hardware to "keep trying"?
I.e., if it just stops scheduling a TXQ after may_transmit() returns
false, there is no guarantee that that TXQ will ever get re-awoken
unless a new packet arrives for it?
That is true and even now ath10k operates the same way in pull mode. Not
just packet arrival, even napi poll routine tries to pushes the packets.
One more thing, fetch indication may pull ~4ms/8ms of packets from each
tid.
This makes deficit too low and so refilling txqs by just airtime_weight
becomes
cumbersome. In may_transmit, the deficit are incremented by 20 *
airtime_weight.
In future this will be also replaced by station specific quantum. we can
revisit
this once BQL in place. Performance issue is resolved by this approach.
Do you foresee any issues?
#define IEEE80211_TXQ_MAY_TX_QUANTUM 20
bool ieee80211_txq_may_transmit(struct ieee80211_hw *hw,
struct ieee80211_txq *txq)
{
struct ieee80211_local *local = hw_to_local(hw);
struct txq_info *txqi = to_txq_info(txq);
struct sta_info *sta;
u8 ac = txq->ac;
lockdep_assert_held(&local->active_txq_lock[ac]);
if (!txqi->txq.sta)
goto out;
sta = container_of(txqi->txq.sta, struct sta_info, sta);
if (sta->airtime[ac].deficit >= 0)
goto out;
list_for_each_entry(txqi, &local->active_txqs[ac],
schedule_order) {
if (!txqi->txq.sta)
continue;
sta = container_of(txqi->txq.sta, struct sta_info, sta);
sta->airtime[ac].deficit +=
(IEEE80211_TXQ_MAY_TX_QUANTUM *
sta->airtime_weight);
}
return false;
out:
list_del_init(&txqi->schedule_order);
return true;
}
-Rajkumar
