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authorMartin Sustrik <sustrik@250bpm.com>2010-05-04 10:22:16 +0200
committerMartin Sustrik <sustrik@250bpm.com>2010-05-04 10:22:16 +0200
commit235ed3a3dcffb7c658cbc9253eae9de54db24533 (patch)
treeb4e91746fea5fe05500aab925720905f1c68fb0c /src
parent8b9bd05726c3df56d7f437889abccba3cbbffdee (diff)
signaler transports commands per se rather than one-bit signals
Diffstat (limited to 'src')
-rw-r--r--src/app_thread.cpp20
-rw-r--r--src/config.hpp5
-rw-r--r--src/dispatcher.cpp71
-rw-r--r--src/dispatcher.hpp30
-rw-r--r--src/io_thread.cpp17
-rw-r--r--src/object.cpp6
-rw-r--r--src/pipe.hpp2
-rw-r--r--src/signaler.cpp224
-rw-r--r--src/signaler.hpp45
-rw-r--r--src/ypipe.hpp83
10 files changed, 174 insertions, 329 deletions
diff --git a/src/app_thread.cpp b/src/app_thread.cpp
index bd5f5e3..1c06337 100644
--- a/src/app_thread.cpp
+++ b/src/app_thread.cpp
@@ -82,9 +82,12 @@ zmq::signaler_t *zmq::app_thread_t::get_signaler ()
bool zmq::app_thread_t::process_commands (bool block_, bool throttle_)
{
- uint32_t signal;
- if (block_)
- signal = signaler.poll ();
+ bool received;
+ command_t cmd;
+ if (block_) {
+ received = signaler.recv (&cmd, true);
+ zmq_assert (received);
+ }
else {
#if defined ZMQ_DELAY_COMMANDS
@@ -117,15 +120,12 @@ bool zmq::app_thread_t::process_commands (bool block_, bool throttle_)
#endif
// Check whether there are any commands pending for this thread.
- signal = signaler.check ();
+ received = signaler.recv (&cmd, false);
}
- // Process all the commands from the signaling source if there is one.
- if (signal != signaler_t::no_signal) {
- command_t cmd;
- while (get_dispatcher ()->read (signal, get_thread_slot (), &cmd))
- cmd.destination->process_command (cmd);
- }
+ // Process the command, if any.
+ if (received)
+ cmd.destination->process_command (cmd);
return !terminated;
}
diff --git a/src/config.hpp b/src/config.hpp
index 99c9d86..5b51a08 100644
--- a/src/config.hpp
+++ b/src/config.hpp
@@ -32,11 +32,6 @@ namespace zmq
// memory allocation by approximately 99.6%
message_pipe_granularity = 256,
- // Number of new commands in command pipe needed to trigger new memory
- // allocation. The number should be kept low to decrease the memory
- // footprint of dispatcher.
- command_pipe_granularity = 4,
-
// Number of signals that can be read by the signaler
// using a single system call.
signal_buffer_size = 8,
diff --git a/src/dispatcher.cpp b/src/dispatcher.cpp
index b1ba11f..db06d32 100644
--- a/src/dispatcher.cpp
+++ b/src/dispatcher.cpp
@@ -18,6 +18,7 @@
*/
#include <new>
+#include <string.h>
#include "../include/zmq.h"
@@ -48,35 +49,30 @@ zmq::dispatcher_t::dispatcher_t (uint32_t app_threads_, uint32_t io_threads_) :
HIBYTE (wsa_data.wVersion) == 2);
#endif
- // Create application thread proxies.
- for (uint32_t i = 0; i != app_threads_; i++) {
- app_thread_info_t info;
- info.associated = false;
- info.app_thread = new (std::nothrow) app_thread_t (this, i);
- zmq_assert (info.app_thread);
- app_threads.push_back (info);
- signalers.push_back (info.app_thread->get_signaler ());
- }
+ // Initialise the array of signalers.
+ signalers_count = app_threads_ + io_threads_;
+ signalers = (signaler_t**) malloc (sizeof (signaler_t*) * signalers_count);
+ zmq_assert (signalers);
+ memset (signalers, 0, sizeof (signaler_t*) * signalers_count);
// Create I/O thread objects.
for (uint32_t i = 0; i != io_threads_; i++) {
- io_thread_t *io_thread = new (std::nothrow) io_thread_t (this,
- i + app_threads_);
+ io_thread_t *io_thread = new (std::nothrow) io_thread_t (this, i);
zmq_assert (io_thread);
io_threads.push_back (io_thread);
- signalers.push_back (io_thread->get_signaler ());
+ signalers [i] = io_thread->get_signaler ();
}
- // Create the administrative thread. Nothing special is needed. NULL
- // is used instead of signaler given that as for now, administrative
- // thread doesn't receive any commands. The only thing it is used for
- // is sending 'stop' command to I/O threads on shutdown.
- signalers.push_back (NULL);
-
- // Create command pipe matrix.
- command_pipes = new (std::nothrow) command_pipe_t [signalers.size () *
- signalers.size ()];
- zmq_assert (command_pipes);
+ // Create application thread proxies.
+ for (uint32_t i = 0; i != app_threads_; i++) {
+ app_thread_info_t info;
+ info.associated = false;
+ info.app_thread = new (std::nothrow) app_thread_t (this,
+ i + io_threads_);
+ zmq_assert (info.app_thread);
+ app_threads.push_back (info);
+ signalers [i + io_threads_] = info.app_thread->get_signaler ();
+ }
// Launch I/O threads.
for (uint32_t i = 0; i != io_threads_; i++)
@@ -123,12 +119,11 @@ zmq::dispatcher_t::~dispatcher_t ()
while (!pipes.empty ())
delete *pipes.begin ();
- // TODO: Deallocate any commands still in the pipes. Keep in mind that
- // simple reading from a pipe and deallocating commands won't do as
- // command pipe has template parameter D set to true, meaning that
- // read may return false even if there are still commands in the pipe.
- delete [] command_pipes;
-
+ // Deallocate the array of pointers to signalers. No special work is
+ // needed as signalers themselves were deallocated with their
+ // corresponding (app_/io_) thread objects.
+ free (signalers);
+
#ifdef ZMQ_HAVE_WINDOWS
// On Windows, uninitialise socket layer.
int rc = WSACleanup ();
@@ -136,11 +131,6 @@ zmq::dispatcher_t::~dispatcher_t ()
#endif
}
-uint32_t zmq::dispatcher_t::thread_slot_count ()
-{
- return (uint32_t) signalers.size ();
-}
-
zmq::socket_base_t *zmq::dispatcher_t::create_socket (int type_)
{
app_threads_sync.lock ();
@@ -213,21 +203,16 @@ void zmq::dispatcher_t::no_sockets (app_thread_t *thread_)
app_threads_sync.unlock ();
}
-void zmq::dispatcher_t::write (uint32_t source_, uint32_t destination_,
+void zmq::dispatcher_t::send_command (uint32_t destination_,
const command_t &command_)
{
- command_pipe_t &pipe =
- command_pipes [source_ * signalers.size () + destination_];
- pipe.write (command_);
- if (!pipe.flush ())
- signalers [destination_]->signal (source_);
+ signalers [destination_]->send (command_);
}
-bool zmq::dispatcher_t::read (uint32_t source_, uint32_t destination_,
- command_t *command_)
+bool zmq::dispatcher_t::recv_command (uint32_t thread_slot_,
+ command_t *command_, bool block_)
{
- return command_pipes [source_ * signalers.size () +
- destination_].read (command_);
+ return signalers [thread_slot_]->recv (command_, block_);
}
zmq::io_thread_t *zmq::dispatcher_t::choose_io_thread (uint64_t affinity_)
diff --git a/src/dispatcher.hpp b/src/dispatcher.hpp
index 0a1ed5c..0986e8a 100644
--- a/src/dispatcher.hpp
+++ b/src/dispatcher.hpp
@@ -27,7 +27,6 @@
#include "signaler.hpp"
#include "ypipe.hpp"
-#include "command.hpp"
#include "config.hpp"
#include "mutex.hpp"
#include "stdint.hpp"
@@ -69,19 +68,12 @@ namespace zmq
// should disassociate the object from the current OS thread.
void no_sockets (class app_thread_t *thread_);
- // Returns number of thread slots in the dispatcher. To be used by
- // individual threads to find out how many distinct signals can be
- // received.
- uint32_t thread_slot_count ();
+ // Send command to the destination thread.
+ void send_command (uint32_t destination_, const command_t &command_);
- // Send command from the source to the destination.
- void write (uint32_t source_, uint32_t destination_,
- const command_t &command_);
-
- // Receive command from the source. Returns false if there is no
- // command available.
- bool read (uint32_t source_, uint32_t destination_,
- command_t *command_);
+ // Receive command from another thread.
+ bool recv_command (uint32_t thread_slot_, command_t *command_,
+ bool block_);
// Returns the I/O thread that is the least busy at the moment.
// Taskset specifies which I/O threads are eligible (0 = all).
@@ -126,15 +118,9 @@ namespace zmq
typedef std::vector <class io_thread_t*> io_threads_t;
io_threads_t io_threads;
- // Signalers for both application and I/O threads.
- std::vector <signaler_t*> signalers;
-
- // Pipe to hold the commands.
- typedef ypipe_t <command_t, true,
- command_pipe_granularity> command_pipe_t;
-
- // NxN matrix of command pipes.
- command_pipe_t *command_pipes;
+ // Array of pointers to signalers for both application and I/O threads.
+ int signalers_count;
+ signaler_t **signalers;
// As pipes may reside in orphaned state in particular moments
// of the pipe shutdown process, i.e. neither pipe reader nor
diff --git a/src/io_thread.cpp b/src/io_thread.cpp
index b38f58c..92c314a 100644
--- a/src/io_thread.cpp
+++ b/src/io_thread.cpp
@@ -22,10 +22,8 @@
#include "../include/zmq.h"
#include "io_thread.hpp"
-#include "command.hpp"
#include "platform.hpp"
#include "err.hpp"
-#include "command.hpp"
#include "dispatcher.hpp"
zmq::io_thread_t::io_thread_t (dispatcher_t *dispatcher_,
@@ -67,17 +65,18 @@ int zmq::io_thread_t::get_load ()
void zmq::io_thread_t::in_event ()
{
+ // TODO: Do we want to limit number of commands I/O thread can
+ // process in a single go?
+
while (true) {
- // Get the next signal.
- uint32_t signal = signaler.check ();
- if (signal == signaler_t::no_signal)
+ // Get the next command. If there is none, exit.
+ command_t cmd;
+ if (!signaler.recv (&cmd, false))
break;
- // Process all the commands from the thread that sent the signal.
- command_t cmd;
- while (get_dispatcher ()->read (signal, get_thread_slot (), &cmd))
- cmd.destination->process_command (cmd);
+ // Process the command.
+ cmd.destination->process_command (cmd);
}
}
diff --git a/src/object.cpp b/src/object.cpp
index 38eb1f8..c5c89cb 100644
--- a/src/object.cpp
+++ b/src/object.cpp
@@ -157,11 +157,10 @@ void zmq::object_t::send_stop ()
{
// 'stop' command goes always from administrative thread to
// the current object.
- uint32_t admin_thread_id = dispatcher->thread_slot_count () - 1;
command_t cmd;
cmd.destination = this;
cmd.type = command_t::stop;
- dispatcher->write (admin_thread_id, thread_slot, cmd);
+ dispatcher->send_command (thread_slot, cmd);
}
void zmq::object_t::send_plug (owned_t *destination_, bool inc_seqnum_)
@@ -370,7 +369,6 @@ void zmq::object_t::process_seqnum ()
void zmq::object_t::send_command (command_t &cmd_)
{
- uint32_t destination_thread_slot = cmd_.destination->get_thread_slot ();
- dispatcher->write (thread_slot, destination_thread_slot, cmd_);
+ dispatcher->send_command (cmd_.destination->get_thread_slot (), cmd_);
}
diff --git a/src/pipe.hpp b/src/pipe.hpp
index a4569e3..b0428b5 100644
--- a/src/pipe.hpp
+++ b/src/pipe.hpp
@@ -145,7 +145,7 @@ namespace zmq
};
// Message pipe.
- class pipe_t : public ypipe_t <zmq_msg_t, false, message_pipe_granularity>
+ class pipe_t : public ypipe_t <zmq_msg_t, message_pipe_granularity>
{
public:
diff --git a/src/signaler.cpp b/src/signaler.cpp
index e1fa6a3..0fa43f7 100644
--- a/src/signaler.cpp
+++ b/src/signaler.cpp
@@ -30,52 +30,9 @@
#else
#include <unistd.h>
#include <fcntl.h>
+#include <limits.h>
#endif
-const uint32_t zmq::signaler_t::no_signal = 0xffffffff;
-
-uint32_t zmq::signaler_t::poll ()
-{
- // Return next signal.
- if (current != count) {
- uint32_t result = buffer [current];
- current++;
- return result;
- }
-
- // If there is no signal buffered, poll for new signals.
- xpoll ();
-
- // Return first signal.
- zmq_assert (current != count);
- uint32_t result = buffer [current];
- current++;
- return result;
-}
-
-uint32_t zmq::signaler_t::check ()
-{
- // Return next signal.
- if (current != count) {
- uint32_t result = buffer [current];
- current++;
- return result;
- }
-
- // If there is no signal buffered, check whether more signals
- // can be obtained.
- xcheck ();
-
- // Return first signal if any.
- if (current != count) {
- uint32_t result = buffer [current];
- current++;
- return result;
- }
-
- return no_signal;
-}
-
zmq::fd_t zmq::signaler_t::get_fd ()
{
return r;
@@ -84,8 +41,6 @@ zmq::fd_t zmq::signaler_t::get_fd ()
#if defined ZMQ_HAVE_WINDOWS
zmq::signaler_t::signaler_t () :
- current (0),
- count (0)
{
// Windows have no 'socketpair' function. CreatePipe is no good as pipe
// handles cannot be polled on. Here we create the socketpair by hand.
@@ -146,51 +101,49 @@ zmq::signaler_t::~signaler_t ()
wsa_assert (rc != SOCKET_ERROR);
}
-void zmq::signaler_t::signal (uint32_t signal_)
+void zmq::signaler_t::send (const command_t &cmd_)
{
// TODO: Note that send is a blocking operation.
// How should we behave if the signal cannot be written to the signaler?
- int rc = send (w, (char*) &signal_, sizeof (signal_), 0);
+ // Even worse: What if half of a command is written?
+ int rc = send (w, (char*) &cmd_, sizeof (command_t), 0);
win_assert (rc != SOCKET_ERROR);
- zmq_assert (rc == sizeof (signal_));
+ zmq_assert (rc == sizeof (command_t));
}
-void zmq::signaler_t::xpoll ()
+bool zmq::signaler_t::recv (command_t *cmd_, bool block_)
{
- // Switch to blocking mode.
- unsigned long argp = 0;
- int rc = ioctlsocket (r, FIONBIO, &argp);
- wsa_assert (rc != SOCKET_ERROR);
+ if (block_) {
- // Get the signals. Given that we are in the blocking mode now,
- // there should be at least a single signal returned.
- xcheck ();
- zmq_assert (current != count);
+ // Switch to blocking mode.
+ unsigned long argp = 0;
+ int rc = ioctlsocket (r, FIONBIO, &argp);
+ wsa_assert (rc != SOCKET_ERROR);
+ }
- // Switch back to non-blocking mode.
- argp = 1;
- rc = ioctlsocket (r, FIONBIO, &argp);
- wsa_assert (rc != SOCKET_ERROR);
-}
+ bool result;
+ int nbytes = recv (r, (char*) cmd_, sizeof (command_t), 0);
+ if (nbytes == -1 && WSAGetLastError () == WSAEWOULDBLOCK) {
+ result = false;
+ }
+ else {
+ wsa_assert (nbytes != -1);
-void zmq::signaler_t::xcheck ()
-{
- int nbytes = recv (r, (char*) buffer, sizeof (buffer), 0);
+ // Check whether we haven't got half of a signal.
+ zmq_assert (nbytes % sizeof (uint32_t) == 0);
- // No signals are available.
- if (nbytes == -1 && WSAGetLastError () == WSAEWOULDBLOCK) {
- current = 0;
- count = 0;
- return;
+ result = true;
}
- wsa_assert (nbytes != -1);
+ if (block_) {
- // Check whether we haven't got half of a signal.
- zmq_assert (nbytes % sizeof (uint32_t) == 0);
+ // Switch back to non-blocking mode.
+ unsigned long argp = 1;
+ int rc = ioctlsocket (r, FIONBIO, &argp);
+ wsa_assert (rc != SOCKET_ERROR);
+ }
- current = 0;
- count = nbytes / sizeof (uint32_t);
+ return result;
}
#elif defined ZMQ_HAVE_HPUX || defined ZMQ_HAVE_AIX
@@ -198,9 +151,7 @@ void zmq::signaler_t::xcheck ()
#include <sys/types.h>
#include <sys/socket.h>
-zmq::signaler_t::signaler_t () :
- current (0),
- count (0)
+zmq::signaler_t::signaler_t ()
{
int sv [2];
int rc = socketpair (AF_UNIX, SOCK_STREAM, 0, sv);
@@ -222,49 +173,50 @@ zmq::signaler_t::~signaler_t ()
close (r);
}
-void zmq::signaler_t::signal (uint32_t signal_)
+void zmq::signaler_t::send (const command_t &cmd_)
{
- ssize_t nbytes = send (w, &signal_, sizeof (signal_), 0);
+ ssize_t nbytes = send (w, &cmd_, sizeof (command_t), 0);
errno_assert (nbytes != -1);
- zmq_assert (nbytes == sizeof (signal_);
+ zmq_assert (nbytes == sizeof (command_t));
}
-void zmq::signaler_t::xpoll ()
+bool zmq::signaler_t::recv (command_t &cmd_, bool block_)
{
- // Set the reader to blocking mode.
- int flags = fcntl (r, F_GETFL, 0);
- if (flags == -1)
- flags = 0;
- int rc = fcntl (r, F_SETFL, flags & ~O_NONBLOCK);
- errno_assert (rc != -1);
+ if (block_) {
+
+ // Set the reader to blocking mode.
+ int flags = fcntl (r, F_GETFL, 0);
+ if (flags == -1)
+ flags = 0;
+ int rc = fcntl (r, F_SETFL, flags & ~O_NONBLOCK);
+ errno_assert (rc != -1);
+ }
- // Poll for events.
- xcheck ();
- zmq_assert (current != count);
+ bool result;
+ ssize_t nbytes = recv (r, buffer, sizeof (command_t), 0);
+ if (nbytes == -1 && errno == EAGAIN) {
+ result = false;
+ }
+ else {
+ zmq_assert (nbytes != -1);
- // Set the reader to non-blocking mode.
- flags = fcntl (r, F_GETFL, 0);
- if (flags == -1)
- flags = 0;
- rc = fcntl (r, F_SETFL, flags | O_NONBLOCK);
- errno_assert (rc != -1);
-}
+ // Check whether we haven't got half of command.
+ zmq_assert (nbytes == sizeof (command_t));
-void zmq::signaler_t::xcheck ()
-{
- ssize_t nbytes = recv (r, buffer, sizeof (buffer), 0);
- if (nbytes == -1 && errno == EAGAIN) {
- current = 0;
- count = 0;
- return;
+ result = true;
}
- zmq_assert (nbytes != -1);
- // Check whether we haven't got half of a signal.
- zmq_assert (nbytes % sizeof (uint32_t) == 0);
+ if (block_)
+
+ // Set the reader to non-blocking mode.
+ int flags = fcntl (r, F_GETFL, 0);
+ if (flags == -1)
+ flags = 0;
+ int rc = fcntl (r, F_SETFL, flags | O_NONBLOCK);
+ errno_assert (rc != -1);
+ }
- current = 0;
- count = nbytes / sizeof (uint32_t);
+ return result;
}
#else
@@ -272,10 +224,13 @@ void zmq::signaler_t::xcheck ()
#include <sys/types.h>
#include <sys/socket.h>
-zmq::signaler_t::signaler_t () :
- current (0),
- count (0)
+zmq::signaler_t::signaler_t ()
{
+ // Make sure that command can be written to the socket in atomic fashion.
+ // If this wasn't guaranteed, commands from different threads would be
+ // interleaved.
+ zmq_assert (sizeof (command_t) <= PIPE_BUF);
+
int sv [2];
int rc = socketpair (AF_UNIX, SOCK_STREAM, 0, sv);
errno_assert (rc == 0);
@@ -289,42 +244,33 @@ zmq::signaler_t::~signaler_t ()
close (r);
}
-void zmq::signaler_t::signal (uint32_t signal_)
+void zmq::signaler_t::send (const command_t &cmd_)
{
// TODO: Note that send is a blocking operation.
- // How should we behave if the signal cannot be written to the signaler?
- ssize_t nbytes = send (w, &signal_, sizeof (signal_), 0);
+ // How should we behave if the command cannot be written to the signaler?
+ ssize_t nbytes = ::send (w, &cmd_, sizeof (command_t), 0);
errno_assert (nbytes != -1);
- zmq_assert (nbytes == sizeof (signal_));
+
+ // This should never happen as we've already checked that command size is
+ // less than PIPE_BUF.
+ zmq_assert (nbytes == sizeof (command_t));
}
-void zmq::signaler_t::xpoll ()
+bool zmq::signaler_t::recv (command_t *cmd_, bool block_)
{
- ssize_t nbytes = recv (r, buffer, sizeof (buffer), 0);
- errno_assert (nbytes != -1);
-
- // Check whether we haven't got half of a signal.
- zmq_assert (nbytes % sizeof (uint32_t) == 0);
+ ssize_t nbytes = ::recv (r, cmd_, sizeof (command_t),
+ block_ ? 0 : MSG_DONTWAIT);
- current = 0;
- count = nbytes / sizeof (uint32_t);
-}
+ // If there's no signal available return false.
+ if (nbytes == -1 && errno == EAGAIN)
+ return false;
-void zmq::signaler_t::xcheck ()
-{
- ssize_t nbytes = recv (r, buffer, 64, MSG_DONTWAIT);
- if (nbytes == -1 && errno == EAGAIN) {
- current = 0;
- count = 0;
- return;
- }
errno_assert (nbytes != -1);
- // Check whether we haven't got half of a signal.
- zmq_assert (nbytes % sizeof (uint32_t) == 0);
+ // Check whether we haven't got half of command.
+ zmq_assert (nbytes == sizeof (command_t));
- current = 0;
- count = nbytes / sizeof (uint32_t);
+ return true;
}
#endif
diff --git a/src/signaler.hpp b/src/signaler.hpp
index 5509894..64a1899 100644
--- a/src/signaler.hpp
+++ b/src/signaler.hpp
@@ -26,15 +26,11 @@
#include "fd.hpp"
#include "stdint.hpp"
#include "config.hpp"
+#include "command.hpp"
namespace zmq
{
- // This object can be used to send individual signals from one thread to
- // another. The specific of this pipe is that it has associated file
- // descriptor and so it can be polled on. Same signal cannot be sent twice
- // unless signals are retrieved by the reader side in the meantime.
-
class signaler_t
{
public:
@@ -42,44 +38,29 @@ namespace zmq
signaler_t ();
~signaler_t ();
- static const uint32_t no_signal;
-
- void signal (uint32_t signal_);
- uint32_t poll ();
- uint32_t check ();
fd_t get_fd ();
-
+ void send (const command_t &cmd_);
+ bool recv (command_t *cmd_, bool block_);
+
private:
- void xpoll ();
- void xcheck ();
-
#if defined ZMQ_HAVE_OPENVMS
- // Whilst OpenVMS supports socketpair - it maps to AF_INET only.
- // Further, it does not set the socket options TCP_NODELAY and
- // TCP_NODELACK which can lead to performance problems. We'll
- // overload the socketpair function for this class.
- //
- // The bug will be fixed in V5.6 ECO4 and beyond. In the
- // meantime, we'll create the socket pair manually.
- static int socketpair (int domain_, int type_, int protocol_,
- int sv_ [2]);
+ // Whilst OpenVMS supports socketpair - it maps to AF_INET only.
+ // Further, it does not set the socket options TCP_NODELAY and
+ // TCP_NODELACK which can lead to performance problems. We'll
+ // overload the socketpair function for this class.
+ //
+ // The bug will be fixed in V5.6 ECO4 and beyond. In the
+ // meantime, we'll create the socket pair manually.
+ static int socketpair (int domain_, int type_, int protocol_,
+ int sv_ [2]);
#endif
// Write & read end of the socketpair.
fd_t w;
fd_t r;
- // Signal buffer.
- uint32_t buffer [signal_buffer_size];
-
- // Position of the next signal in the buffer to return to the user.
- size_t current;
-
- // Number of signals in the signal buffer.
- size_t count;
-
// Disable copying of fd_signeler object.
signaler_t (const signaler_t&);
void operator = (const signaler_t&);
diff --git a/src/ypipe.hpp b/src/ypipe.hpp
index 83ae6a7..445b487 100644
--- a/src/ypipe.hpp
+++ b/src/ypipe.hpp
@@ -30,31 +30,24 @@ namespace zmq
// Lock-free queue implementation.
// Only a single thread can read from the pipe at any specific moment.
// Only a single thread can write to the pipe at any specific moment.
- //
// T is the type of the object in the queue.
- // If the template parameter D is set to true, it is quaranteed that
- // the pipe will die in a finite time (so that you can swich to some
- // other task). If D is set to false, reading from the pipe may result
- // in an infinite cycle (if the pipe is continuosly fed by new elements).
- // N is granularity of the pipe (how many elements have to be inserted
- // till actual memory allocation is required).
-
- template <typename T, bool D, int N> class ypipe_t
+ // N is granularity of the pipe, i.e. how many messages are needed to
+ // perform next memory allocation.
+
+ template <typename T, int N> class ypipe_t
{
public:
- // Initialises the pipe. In D scenario it is created in dead state.
- // Otherwise it's alive.
- inline ypipe_t () :
- stop (false)
+ // Initialises the pipe.
+ inline ypipe_t ()
{
// Insert terminator element into the queue.
queue.push ();
- // Let all the pointers to point to the terminator
+ // Let all the pointers to point to the terminator.
// (unless pipe is dead, in which case c is set to NULL).
r = w = &queue.back ();
- c.set (D ? NULL : &queue.back ());
+ c.set (&queue.back ());
}
// Following function (write) deliberately copies uninitialised data
@@ -125,50 +118,17 @@ namespace zmq
return true;
// There's no prefetched value, so let us prefetch more values.
- // (Note that D is a template parameter. Becaue of that one of
- // the following branches will be completely optimised away
- // by the compiler.)
- if (D) {
-
- // If one prefetch was already done since last sleeping,
- // don't do a new one, rather ask caller to go asleep.
- if (stop) {
- stop = false;
- return false;
- }
-
- // Get new items. Perform the operation in atomic fashion.
- r = c.xchg (NULL);
-
- // If there are no elements prefetched, exit and go asleep.
- // During pipe's lifetime r should never be NULL, however,
- // during pipe shutdown when retrieving messages from it
- // to deallocate them, this can happen.
- if (&queue.front () == r || !r) {
- stop = false;
- return false;
- }
-
- // We want to do only a single prefetch in D scenario
- // before going asleep. Thus, we set stop variable to true
- // so that we can return false next time the prefetch is
- // attempted.
- stop = true;
- }
- else {
-
- // Prefetching in non-D scenario is to simply retrieve the
- // pointer from c in atomic fashion. If there are no
- // items to prefetch, set c to NULL (using compare-and-swap).
- r = c.cas (&queue.front (), NULL);
-
- // If there are no elements prefetched, exit.
- // During pipe's lifetime r should never be NULL, however,
- // it can happen during pipe shutdown when messages
- // are being deallocated.
- if (&queue.front () == r || !r)
- return false;
- }
+ // Prefetching is to simply retrieve the
+ // pointer from c in atomic fashion. If there are no
+ // items to prefetch, set c to NULL (using compare-and-swap).
+ r = c.cas (&queue.front (), NULL);
+
+ // If there are no elements prefetched, exit.
+ // During pipe's lifetime r should never be NULL, however,
+ // it can happen during pipe shutdown when messages
+ // are being deallocated.
+ if (&queue.front () == r || !r)
+ return false;
// There was at least one value prefetched.
return true;
@@ -211,11 +171,6 @@ namespace zmq
// atomic operations.
atomic_ptr_t <T> c;
- // Used only if 'D' template parameter is set to true. If true,
- // prefetch was already done since last sleeping and the reader
- // should go asleep instead of prefetching once more.
- bool stop;
-
// Disable copying of ypipe object.
ypipe_t (const ypipe_t&);
void operator = (const ypipe_t&);