[zeromq-dev] adding timeout in zmq_poll
pavimus at gmail.com
Tue Dec 29 00:25:52 CET 2009
I did patch, but when i tried to test it, something goes wrong. I
tried my test program on unmodified zmq2 and get same problem.
I attached modified display.cpp (that binds to some address) and
prompt.cpp that connects to it. When i try to start display:
i get error:
Assertion failed: false (sub.cpp:155)
What i'm doing wrong?
I found discrepancy in zmq_poll manpage. in zmq_pollitem_t section
ZMQ_POLLIN and ZMQ_POLLOUT is discussed, but in example section only
POLLIN is used.
2009/12/28 Martin Sustrik <sustrik at 250bpm.com>:
> Pavel Gushcha wrote:
>> 2) If user specified too small timeout (1 nsec) must we increase
>> this timeout to one ms in linux and 1microsec in windows?
>> I would rather decrease the number. The semantics of the timeout is
>> "zmq_poll will return before the timeout expires" (see the previous
>> discussion on returning with no events).
>> If specified timeout is greater than OS API timeout granularity we can
>> without problem decrease it. I speak about case, when user specified timeout
>> lesser, than timeout granularity in OS API. Timeout will be calculated as
>> zero and user will get 100% cpu usage in thread that executes zmq_poll() in
> I don't think that's a problem. If you specify very low timeout, high CPU
> usage is to be expected. It's a natural behaviour.
> On the other hand, not adhering to timing guarantees can cause serious
> problems in real-time applications.
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