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eventfd implementation of the signaler

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Eventfd (on Linux) is more efficient that socketpair
for passing simple signals.

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
This commit is contained in:
Martin Sustrik 2011-07-03 15:13:57 +02:00
parent da26134aa6
commit 9a9a0cf410
2 changed files with 38 additions and 6 deletions
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42
src/signaler.cpp
View File

@ -57,10 +57,15 @@
#include "signaler.hpp"
#include "likely.hpp"
#include "stdint.hpp"
#include "err.hpp"
#include "fd.hpp"
#include "ip.hpp"
#if defined ZMQ_HAVE_EVENTFD
#include <sys/eventfd.h>
#endif
#if defined ZMQ_HAVE_WINDOWS
#include "windows.hpp"
#else
@ -100,14 +105,19 @@ zmq::signaler_t::signaler_t ()
zmq::signaler_t::~signaler_t ()
{
#if defined ZMQ_HAVE_WINDOWS
#if defined ZMQ_HAVE_EVENTFD
int rc = close (r);
errno_assert (rc == 0);
#elif defined ZMQ_HAVE_WINDOWS
int rc = closesocket (w);
wsa_assert (rc != SOCKET_ERROR);
rc = closesocket (r);
wsa_assert (rc != SOCKET_ERROR);
#else
close (w);
close (r);
int rc = close (w);
errno_assert (rc == 0);
rc = close (r);
errno_assert (rc == 0);
#endif
}
@ -118,7 +128,11 @@ zmq::fd_t zmq::signaler_t::get_fd ()
void zmq::signaler_t::send ()
{
#if defined ZMQ_HAVE_WINDOWS
#if defined ZMQ_HAVE_EVENTFD
const uint64_t inc = 1;
ssize_t sz = write (w, &inc, sizeof (inc));
errno_assert (sz == sizeof (inc));
#elif defined ZMQ_HAVE_WINDOWS
unsigned char dummy = 0;
int nbytes = ::send (w, &dummy, sizeof (dummy), 0);
wsa_assert (nbytes != SOCKET_ERROR);
@ -188,6 +202,14 @@ int zmq::signaler_t::wait (int timeout_)
void zmq::signaler_t::recv ()
{
// Attempt to read a signal.
#if defined ZMQ_HAVE_EVENTFD
uint64_t dummy;
ssize_t sz = read (r, &dummy, sizeof (dummy));
errno_assert (sz == sizeof (dummy));
if (dummy != 1)
printf ("dummy:%d\n", (int) dummy);
zmq_assert (dummy == 1);
#else
unsigned char dummy;
#if ZMQ_HAVE_WINDOWS
int nbytes = ::recv (r, &dummy, sizeof (dummy), 0);
@ -198,11 +220,21 @@ void zmq::signaler_t::recv ()
#endif
zmq_assert (nbytes == sizeof (dummy));
zmq_assert (dummy == 0);
#endif
}
int zmq::signaler_t::make_fdpair (fd_t *r_, fd_t *w_)
{
#if defined ZMQ_HAVE_WINDOWS
#if defined ZMQ_HAVE_EVENTFD
// Create eventfd object.
fd_t fd = eventfd (0, 0);
errno_assert (fd != -1);
*w_ = fd;
*r_ = fd;
return 0;
#elif defined ZMQ_HAVE_WINDOWS
// Windows has no 'socketpair' function. CreatePipe is no good as pipe
// handles cannot be polled on. Here we create the socketpair by hand.

2
src/signaler.hpp
View File

@ -49,7 +49,7 @@ namespace zmq
// to pass the signals.
static int make_fdpair (fd_t *r_, fd_t *w_);
// Write & read end of the socketpair.
// Underlying write & read file descriptor.
fd_t w;
fd_t r;