On Tue, 2015-02-10 at 15:19 +0100, Johannes Berg wrote:

On Tue, 2015-02-10 at 11:33 +0100, Michal Kazior wrote:

quoted

+       if (msdu->sk) {
+               ewma_add(&ar->tx_delay_us,
+                        ktime_to_ns(ktime_sub(ktime_get(), skb_cb->stamp)) /
+                        NSEC_PER_USEC);
+
+               ACCESS_ONCE(msdu->sk->sk_tx_completion_delay_cushion) =
+                               (ewma_read(&ar->tx_delay_us) *
+                                msdu->sk->sk_pacing_rate) >> 20;
+       }

To some extent, every wifi driver is going to have this problem. Perhaps
we should do this in mac80211?

I'll provide the TCP patch.

sk->sk_tx_completion_delay_cushion is probably a wrong name, as the
units here are in bytes, since it is really number of bytes in the
network driver that accommodate for tx completions delays. 

tx_completion_delay * pacing_rate

sk_tx_completion_cushion maybe.