My new test setup is
rpi2--archer c7----(wifi)-fedora laptop (atheros wifi and fq_codel by default)

The results are somewhat not what I expected. I am seeing relatively
large latencies at close range for the rpi2 server which is plugged
into the archer v2 in-built switch.

Any pointer as to what I need to tweak to reach 40ms latency under load ?

root@lede:/sys# cat kernel/debug/ieee80211/phy1/netdev\:wlan1/aqm
ac backlog-bytes backlog-packets new-flows drops marks overlimit
collisions tx-bytes tx-packets
2 0 0 187 0 0 0 0 39948 187