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Subject: Re: Throughput regression with `tcp: refine TSO autosizing`
From: Johannes Berg <johannes@sipsolutions.net>
To: Michal Kazior <michal.kazior@tieto.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
	Neal Cardwell <ncardwell@google.com>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	Network Development <netdev@vger.kernel.org>,
	Eyal Perry <eyalpe@dev.mellanox.co.il>
Date: Tue, 10 Feb 2015 15:19:22 +0100
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On Tue, 2015-02-10 at 11:33 +0100, Michal Kazior wrote:

> +       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?

johannes