On 2010-12-6 16:48, Martin Sustrik wrote:
> Hi,
>
>> zmq 2.1.0, ZMQ_FD bug
>> pull = zmq_bind(), push = zmq_connect(), libevent + pull, ok!
>> push = zmq_bind(), pull = zmq_connect(), libevent + pull, fail!
>
> What does "fail" main?
>
>> example:
>> https://github.com/kasicass/kasicass/blob/master/zmq/test.c
>
> Can you provide a minimal test case?
>
> Martin
hi Martin,
Here is the detailed description of the problem I encountered. Is it a bug?
//// main thread (ok version) ////
pull = zmq_socket(ZMQ_PULL)
zmq_bind(pull)
push = zmq_socket(ZMQ_PUSH)
zmq_connect(push)
-> zmq::socket_base_t::connect()
-> send_bind() // send 'bind' to pull.mailbox
start thread 2
sleep(1)
while (1)
{
zmq_send(push);
}
//// thread 2 ////
fd = zmq_getsockopt(pull, ZMQ_FD);
while (1)
{
select(fd for read);
zmq_getsockopt(pull, ZMQ_EVENTS);
while (1) zmq_recv(pull, ZMQ_NOBLOCK);
}
// ======== sequence chart ========
//
// thread 2 (first loop):
// select(fd for read); // got
'bind' message
// zmq_getsockopt(pull, ZMQ_EVENTS); // socket_base_t::process_commands()
//
// -> pull attach
//
// pull_t::xhas_in()
//
// -> fq_t::has_in()
//
// -> ypipe_t::check_read()
// //
-> c.cas (&queue.front (), NULL); // c = NULL
// zmq_recv(pull, ZMQ_NOBLOCK); // do nothing, goto to
select() again
//
// main thread:
// zmq_send(push); // push_t::xsend()
// // -> lb_t::send()
// // -> ypipe_t::flush()
// // -> c.cas (w, f) != w
// //
(Compare-and-swap was unseccessful because 'c' is NULL.)
// // -> send
'activate_reader' to pull.mailbox
//
// second loop:
// select(fd for read); // got
'activate_reader' message
// zmq_getsockopt(pull, ZMQ_EVENTS); // socket_base_t::process_commands()
//
// -> fq_t::activated()
//
// pull_t::xhas_in() / set 'ZMQ_POLLIN'
// zmq_recv(pull, ZMQ_NOBLOCK); // consuming all zmq_msg_t
-----------------------------------------------------------------------------
//// main thread (fail version) ////
push = zmq_socket(ZMQ_PUSH)
zmq_bind(push)
pull = zmq_socket(ZMQ_PULL)
zmq_connect(pull)
-> zmq::socket_base_t::connect()
-> send_bind() // send 'bind' to push.mailbox
start thread 2
sleep(1);
while (1)
{
zmq_send(push); // consume the 'bind' message
}
//// thread 2 ////
fd = zmq_getsockopt(pull, ZMQ_FD);
while (1)
{
select(fd for read);
zmq_getsockopt(pull, ZMQ_EVENTS);
while (1) zmq_recv(pull, ZMQ_NOBLOCK);
}
// ======== sequence chart ========
//
// main thread:
// zmq_send(push); // push_t::xsend()
// // -> lb_t::send()
// // -> ypipe_t::flush()
// // -> c.cas (w, f) != w
// // (Compare-and-swap
was unseccessful because 'c' is NULL.)
// // (no
'activate_reader' to pull.mailbox)
//
// thread 2 (first loop):
// select(fd for read); // block here, as no 'activate_reader' message
// ...
--
Kasicass, co...@work
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