Hi all, I am facing a performance issue with a thread running zmq_proxy_steerable(), which subscribes to multiple inproc XPUB sockets and forwards data to a tcp XPUB socket. I am using ZMQ latest version 4.3.1
I noticed a huge amount of calls to poll() that limit the throughput to ~120kpps. From strace output I see: % time seconds usecs/call calls errors syscall ------ ----------- ----------- --------- --------- ---------------- 81.77 1.419731 4 371984 poll 18.22 0.316395 7 45533 write 0.01 0.000106 5 22 read 0.00 0.000015 15 1 restart_syscall ------ ----------- ----------- --------- --------- ---------------- 100.00 1.736247 417540 total If I use gdb to stop on the poll() it seems that most of the time it is called by: zmq::socket_base_t::getsockopt(...) that calls process_command() with flag throttle_=false : const int rc = process_commands (0, false); // socket_base.cpp:450 // prototype: int zmq::socket_base_t::process_commands (int timeout_, bool throttle_) I tried to change that line to throttle=true and to tune the parameters in config.hpp : inbound_poll_rate = 100 -> inbound_poll_rate = 10000 max_command_delay = 3000000 -> max_command_delay = 3000000000 The result is an increase of the throughput from ~120kpps to ~230kpps due to the lower amount of calls to poll(): % time seconds usecs/call calls errors syscall ------ ----------- ----------- --------- --------- ---------------- 55.64 1.278789 4 295038 poll 44.35 1.019367 7 147408 write 0.00 0.000086 4 22 read 0.00 0.000057 10 6 futex ------ ----------- ----------- --------- --------- ---------------- 100.00 2.298299 442474 total Is it safe to enable the throttle in getsockopt()? Is there any side effect beside a maybe longer response time to commands? In case it is safe, do you accept a PR to change throttle=true and make inbound_poll_rate and max_command_delay configurable? Regards, Claudio _______________________________________________ zeromq-dev mailing list [email protected] https://lists.zeromq.org/mailman/listinfo/zeromq-dev
