I have tunned ubuntu 12.04 and YAT. When i try to load some web resource for maximun throughput my YAT can create only 32708 active instaces. Is it a maximum? I changed value of open file descriptors and sockets for maximum but don't have expected result.
If you have not seen yet here some recommendations: https://yandextank.readthedocs.io/en/latest/install.html
But for more guaranteed result try these commands, especially the first one (you could use more adequate number):
echo 10000000 > /proc/sys/kernel/pid_max
sysctl -w net.ipv4.ip_local_port_range="500 65535"
echo 10000000 > /proc/sys/kernel/threads-max
echo 10000000 > /proc/sys/fs/file-max
echo 10000000 > /proc/sys/vm/max_map_count
echo 20000500 > /proc/sys/fs/nr_open