low throughput for tperf using bbr

[habt]

Hi, I used to be able to get a throughput above 420 Mbps while running tperf from an old commit of mvfst (792c0a7) with tperf using BBR over a 500Mbps, 30ms RTT bottleneck. But after updating to the latest mvfst, I am only able to get a throughput of about 60Mbps. My tperf calls are the same for both commits.

server:
./tperf -congestion=bbr -pacing=true --max_cwnd_mss=4294967295 --num_streams=1 -gso=true -max_receive_packet_size=50000 -host=10.10.2.1 -port=6666

client:
./tperf -mode client -congestion=bbr -pacing=true -window 1044674407370955161 -gso=true -max_receive_packet_size=50000 -duration=60 -host=10.10.2.1 -port=6666

I am hoping to know if I am missing any new configuration settings that are required for BBR in latest mvfst versions or if it is something else. Cubic performs the same for both commits.

Thanks,