[zeromq-dev] zmq_poll performance question

[Francis Le Bourse]

Hi,

I am looking at a performance issue in zmq, when the number of zsockets 
/ file descriptors becomes large.
The relevant calls are:
/    poll+0x57//
//    zmq_poll+0x2e3//
//    zloop_start+0x1e8//
//    main+0xb40//
//    __libc_start_main+0xfd//
/immediately followed by a loop of
/    poll+0x57//
//    zmq::signaler_t::wait(int)+0x33//
//    zmq::mailbox_t::recv(zmq::command_t*, int)+0x78//
//    zmq::socket_base_t::process_commands(int, bool)+0xbe//
//    zmq::socket_base_t::getsockopt(int, void*, unsigned long*)+0x135//
//    zmq_getsockopt+0x75//
//    zmq_poll+0x3da//
//    zloop_start+0x1e8//
//    main+0xb40//
//    __libc_start_main+0xfd//
/
The code in the loop is executed once per file descriptor in the initial 
pollarray, redoing a poll() system call each time.
Is there a reason to proceed that way ?
Would be possible to reuse the results of the first poll() in order to 
bypass the second set of system calls ?

Cheers,
Francis

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