2018-10-24 14:26:59

by Tom Psyborg

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Subject: dynack slows down network when enabled on AR9462 card

Hi

Running several tests with dynack enabled on AR9462 card I can see
throughput drop in 10-30Mbps range.

The card is running on 4.9.135 kernel (same issue was present on
3.2.11 with backports4.4.2) while QCA9531 router is running 4.9.111.

Distance between the two is less than 1m. Results:

QCA9531 auto distance + AR9462 default -> 10Mbps higher RX bandwidth
on client (AR9462), RX bandwidth remain unchanged

QCA9531 default + AR9462 auto distance -> at least 10Mbps lower RX
bandwidth and up to 30Mbps (depending on window size) lower TX
bandwidth on client

QCA9531 auto distance + AR9462 auto distance -> at least 10Mbps lower
RX bandwidth and up to 30Mbps (depending on window size) lower TX
bandwidth on client

Given that the bandwidth improves when executed iw phy0 set distance
auto on router and degrades in any case same command is executed on
client PC running AR9462 seems like there are some timers
misconfiguration in ath9k regarding this card. Any thoughts on this?

Regards, Tom