[Make-wifi-fast] [v6] ath9k: Switch to using mac80211 intermediate software queues.
kvalo at qca.qualcomm.com
Wed Nov 9 17:42:56 EST 2016
Toke Høiland-Jørgensen wrote:
> This switches ath9k over to using the mac80211 intermediate software
> queueing mechanism for data packets. It removes the queueing inside the
> driver, except for the retry queue, and instead pulls from mac80211 when
> a packet is needed. The retry queue is used to store a packet that was
> pulled but can't be sent immediately.
> The old code path in ath_tx_start that would queue packets has been
> removed completely, as has the qlen limit tunables (since there's no
> longer a queue in the driver to limit).
> The mac80211 intermediate software queues offer significant latency
> reductions, and this patch allows ath9k to realise them. The exact gains
> from this varies with the test scenario, but in an access point scenario
> we have seen latency reductions ranging from 1/3 to as much as an order
> of magnitude. We also achieve slightly better aggregation.
> Median latency (ping) figures with this patch applied at the access point,
> with two high-rate stations and one low-rate station (HT20 5Ghz), running
> a Flent rtt_fair_var_up test with one TCP flow and one ping flow going to
> each station:
> Fast station Slow station
> Default pfifo_fast qdisc: 430.4 ms 638.7 ms
> fq_codel qdisc on iface: 35.5 ms 211.8 ms
> This patch set: 22.4 ms 38.2 ms
> Median aggregation sizes over the same test:
> Default pfifo_fast qdisc: 9.5 pkts 1.9 pkts
> fq_codel qdisc on iface: 11.2 pkts 1.9 pkts
> This patch set: 13.9 pkts 1.9 pkts
> This patch is based on Tim's original patch set, but reworked quite
> Cc: Tim Shepard <shep at alum.mit.edu>
> Cc: Felix Fietkau <nbd at nbd.name>
> Signed-off-by: Toke Høiland-Jørgensen <toke at toke.dk>
Perfect, just what I was hoping to see :) Unless something really
surprising comes up I should apply this within the next few days.
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