I have a similar issue with this ab is erroring out with apr_socket_recv: Connection refused (61), and I have tried upgrading the new apache bench but the problem still exists. I have no idea whether the problem lies in apache bench or the server. I am using python Gevent Server with bottle framework.
Apache bench version
This is ApacheBench, Version 2.3 <$Revision: 1430300 $>
Trace error
Benchmarking ec2-xx-xx-xx-xx.eu-west-1.compute.amazonaws.com (be patient)
Completed 100 requests
Completed 200 requests
Completed 300 requests
Completed 400 requests
apr_socket_recv: Connection refused (61)
apr_socket_recv: Connection refused (61)
apr_socket_recv: Connection refused (61)
apr_socket_recv: Connection refused (61)
Test aborted after 10 failures
apr_socket_connect(): Operation already in progress (37)
Total of 468 requests completed