[ath10k throughput] low throughput in multi-user mode

[gary]

Hi all,
I have run the throughput test on veriwave.(from Ethernet to wireless)
My AP suports 4*4, 11ac, mu-mimo.,wireless chip is QCA9984.
At first, the throughput is about 80Mbps only with 16 users, so I force to
return true in function ath10k_mac_tx_can_push().
As a result, when the user number is 1~16, the udp throughput is about
1.2Gbps ~1.4Gbps.
But when the user number is 32, the udp throughput is only 520Mbps.

So I try to substitute ath10k-firmware.
With firmware 10.4-3.4-0082 and above, the throughput is around 520Mbps.
But with firmware 10.4-3.4-0072, the throughput gets 1.1Gbps.

Do I miss something in configuration?
Any comment is appreciated.

Thanks.