poller_base_t renamed to io_thread_t

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

66 files changed, 204 insertions, 207 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 7d3ee8d..9f11611 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -23,6 +23,7 @@ libxs_la_SOURCES = \
     fd.hpp \
     fq.hpp \
     io_object.hpp \
+    io_thread.hpp \
     ip.hpp \
     ipc_address.hpp \
     ipc_connecter.hpp \
@@ -45,7 +46,6 @@ libxs_la_SOURCES = \
     pipe.hpp \
     platform.hpp \
     poll.hpp \
-    poller_base.hpp \
     pair.hpp \
     pub.hpp \
     pull.hpp \
@@ -85,6 +85,7 @@ libxs_la_SOURCES = \
     err.cpp \
     fq.cpp \
     io_object.cpp \
+    io_thread.cpp \
     ip.cpp \
     ipc_address.cpp \
     ipc_connecter.cpp \
@@ -104,7 +105,6 @@ libxs_la_SOURCES = \
     pgm_socket.cpp \
     pipe.cpp \
     poll.cpp \
-    poller_base.cpp \
     pull.cpp \
     push.cpp \
     reaper.cpp \
diff --git a/src/ctx.cpp b/src/ctx.cpp
index 8b27b31..789cdc2 100644
--- a/src/ctx.cpp
+++ b/src/ctx.cpp
@@ -197,7 +197,7 @@ xs::socket_base_t *xs::ctx_t::create_socket (int type_)
 
         //  Create I/O thread objects and launch them.
         for (uint32_t i = 2; i != io_thread_count + 2; i++) {
-            poller_base_t *io_thread = poller_base_t::create (this, i);
+            io_thread_t *io_thread = io_thread_t::create (this, i);
             errno_assert (io_thread);
             io_threads.push_back (io_thread);
             slots [i] = io_thread->get_mailbox ();
@@ -226,7 +226,7 @@ xs::socket_base_t *xs::ctx_t::create_socket (int type_)
     #endif
 
         //  Create the monitor object.
-        poller_base_t *io_thread = choose_io_thread (0);
+        io_thread_t *io_thread = choose_io_thread (0);
         xs_assert (io_thread);
         monitor = new (std::nothrow) monitor_t (io_thread);
         alloc_assert (monitor);
@@ -301,7 +301,7 @@ void xs::ctx_t::send_command (uint32_t tid_, const command_t &command_)
     slots [tid_]->send (command_);
 }
 
-xs::poller_base_t *xs::ctx_t::choose_io_thread (uint64_t affinity_)
+xs::io_thread_t *xs::ctx_t::choose_io_thread (uint64_t affinity_)
 {
     if (io_threads.empty ())
         return NULL;
diff --git a/src/ctx.hpp b/src/ctx.hpp
index c12fffc..e912443 100644
--- a/src/ctx.hpp
+++ b/src/ctx.hpp
@@ -40,7 +40,7 @@ namespace xs
 
     class object_t;
     class monitor_t;
-    class poller_base_t;
+    class io_thread_t;
     class socket_base_t;
     class reaper_t;
 
@@ -86,7 +86,7 @@ namespace xs
         //  Returns the I/O thread that is the least busy at the moment.
         //  Affinity specifies which I/O threads are eligible (0 = all).
         //  Returns NULL is no I/O thread is available.
-        xs::poller_base_t *choose_io_thread (uint64_t affinity_);
+        xs::io_thread_t *choose_io_thread (uint64_t affinity_);
 
         //  Returns reaper thread object.
         xs::object_t *get_reaper ();
@@ -142,7 +142,7 @@ namespace xs
         xs::reaper_t *reaper;
 
         //  I/O threads.
-        typedef std::vector <xs::poller_base_t*> io_threads_t;
+        typedef std::vector <xs::io_thread_t*> io_threads_t;
         io_threads_t io_threads;
 
         //  Array of pointers to mailboxes for both application and I/O threads.
diff --git a/src/devpoll.cpp b/src/devpoll.cpp
index e85b765..936d6c2 100644
--- a/src/devpoll.cpp
+++ b/src/devpoll.cpp
@@ -38,7 +38,7 @@
 #include "config.hpp"
 
 xs::devpoll_t::devpoll_t (xs::ctx_t *ctx_, uint32_t tid_) :
-    poller_base_t (ctx_, tid_),
+    io_thread_t (ctx_, tid_),
     stopping (false)
 {
     devpoll_fd = open ("/dev/poll", O_RDWR);
diff --git a/src/devpoll.hpp b/src/devpoll.hpp
index b32aa28..3947f3e 100644
--- a/src/devpoll.hpp
+++ b/src/devpoll.hpp
@@ -30,7 +30,7 @@
 
 #include "fd.hpp"
 #include "thread.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 
 namespace xs
 {
@@ -39,14 +39,14 @@ namespace xs
 
     //  Implements socket polling mechanism using the "/dev/poll" interface.
 
-    class devpoll_t : public poller_base_t
+    class devpoll_t : public io_thread_t
     {
     public:
 
         devpoll_t (xs::ctx_t *ctx_, uint32_t tid_);
         ~devpoll_t ();
 
-        //  "poller" concept.
+        //  Implementation of virtual functions from io_thread_t.
         handle_t add_fd (fd_t fd_, xs::i_poll_events *events_);
         void rm_fd (handle_t handle_);
         void set_pollin (handle_t handle_);
diff --git a/src/epoll.cpp b/src/epoll.cpp
index 7ca4608..aa13b31 100644
--- a/src/epoll.cpp
+++ b/src/epoll.cpp
@@ -35,7 +35,7 @@
 #include "err.hpp"
 
 xs::epoll_t::epoll_t (xs::ctx_t *ctx_, uint32_t tid_) :
-    poller_base_t (ctx_, tid_),
+    io_thread_t (ctx_, tid_),
     stopping (false)
 {
     epoll_fd = epoll_create (1);
diff --git a/src/epoll.hpp b/src/epoll.hpp
index 232d049..ad94120 100644
--- a/src/epoll.hpp
+++ b/src/epoll.hpp
@@ -31,7 +31,7 @@
 
 #include "fd.hpp"
 #include "thread.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 
 namespace xs
 {
@@ -42,14 +42,14 @@ namespace xs
     //  This class implements socket polling mechanism using the Linux-specific
     //  epoll mechanism.
 
-    class epoll_t : public poller_base_t
+    class epoll_t : public io_thread_t
     {
     public:
 
         epoll_t (xs::ctx_t *ctx_, uint32_t tid_);
         ~epoll_t ();
 
-        //  "poller" concept.
+        //  Implementation of virtual functions from io_thread_t.
         handle_t add_fd (fd_t fd_, xs::i_poll_events *events_);
         void rm_fd (handle_t handle_);
         void set_pollin (handle_t handle_);
diff --git a/src/i_engine.hpp b/src/i_engine.hpp
index 9106411..fc03f0e 100644
--- a/src/i_engine.hpp
+++ b/src/i_engine.hpp
@@ -25,7 +25,7 @@
 namespace xs
 {
 
-    class poller_base_t;
+    class io_thread_t;
 
     //  Abstract interface to be implemented by various engines.
 
@@ -34,7 +34,7 @@ namespace xs
         virtual ~i_engine () {}
 
         //  Plug the engine to the session.
-        virtual void plug (xs::poller_base_t *io_thread_,
+        virtual void plug (xs::io_thread_t *io_thread_,
             class session_base_t *session_) = 0;
 
         //  Unplug the engine from the session.
diff --git a/src/io_object.cpp b/src/io_object.cpp
index 0c73571..c17ff04 100644
--- a/src/io_object.cpp
+++ b/src/io_object.cpp
@@ -20,11 +20,11 @@
 */
 
 #include "io_object.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 #include "err.hpp"
 
-xs::io_object_t::io_object_t (poller_base_t *io_thread_) :
-    poller (NULL)
+xs::io_object_t::io_object_t (io_thread_t *io_thread_) :
+    io_thread (NULL)
 {
     if (io_thread_)
         plug (io_thread_);
@@ -34,62 +34,59 @@ xs::io_object_t::~io_object_t ()
 {
 }
 
-void xs::io_object_t::plug (poller_base_t *io_thread_)
+void xs::io_object_t::plug (io_thread_t *io_thread_)
 {
     xs_assert (io_thread_);
-    xs_assert (!poller);
+    xs_assert (!io_thread);
 
-    //  Retrieve the poller from the thread we are running in.
-    poller = io_thread_;
+    //  Retrieve the io_thread from the thread we are running in.
+    io_thread = io_thread_;
 }
 
 void xs::io_object_t::unplug ()
 {
-    xs_assert (poller);
-
-    //  Forget about old poller in preparation to be migrated
-    //  to a different I/O thread.
-    poller = NULL;
+    xs_assert (io_thread);
+    io_thread = NULL;
 }
 
 xs::handle_t xs::io_object_t::add_fd (fd_t fd_)
 {
-    return poller->add_fd (fd_, this);
+    return io_thread->add_fd (fd_, this);
 }
 
 void xs::io_object_t::rm_fd (handle_t handle_)
 {
-    poller->rm_fd (handle_);
+    io_thread->rm_fd (handle_);
 }
 
 void xs::io_object_t::set_pollin (handle_t handle_)
 {
-    poller->set_pollin (handle_);
+    io_thread->set_pollin (handle_);
 }
 
 void xs::io_object_t::reset_pollin (handle_t handle_)
 {
-    poller->reset_pollin (handle_);
+    io_thread->reset_pollin (handle_);
 }
 
 void xs::io_object_t::set_pollout (handle_t handle_)
 {
-    poller->set_pollout (handle_);
+    io_thread->set_pollout (handle_);
 }
 
 void xs::io_object_t::reset_pollout (handle_t handle_)
 {
-    poller->reset_pollout (handle_);
+    io_thread->reset_pollout (handle_);
 }
 
 xs::handle_t xs::io_object_t::add_timer (int timeout_)
 {
-    return poller->add_timer (timeout_, this);
+    return io_thread->add_timer (timeout_, this);
 }
 
 void xs::io_object_t::rm_timer (handle_t handle_)
 {
-    poller->rm_timer (handle_);
+    io_thread->rm_timer (handle_);
 }
 
 void xs::io_object_t::in_event (fd_t fd_)
diff --git a/src/io_object.hpp b/src/io_object.hpp
index 0749ceb..31f9507 100644
--- a/src/io_object.hpp
+++ b/src/io_object.hpp
@@ -25,30 +25,30 @@
 #include <stddef.h>
 
 #include "stdint.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 
 namespace xs
 {
 
     //  Simple base class for objects that live in I/O threads.
-    //  It makes communication with the poller object easier and
+    //  It makes communication with the io_thread object easier and
     //  makes defining unneeded event handlers unnecessary.
 
     class io_object_t : public i_poll_events
     {
     public:
 
-        io_object_t (xs::poller_base_t *io_thread_ = NULL);
+        io_object_t (xs::io_thread_t *io_thread_ = NULL);
         ~io_object_t ();
 
         //  When migrating an object from one I/O thread to another, first
         //  unplug it, then migrate it, then plug it to the new thread.
-        void plug (xs::poller_base_t *io_thread_);
+        void plug (xs::io_thread_t *io_thread_);
         void unplug ();
 
     protected:
 
-        //  Methods to access underlying poller object.
+        //  Methods to access underlying io_thread object.
         handle_t add_fd (fd_t fd_);
         void rm_fd (handle_t handle_);
         void set_pollin (handle_t handle_);
@@ -65,7 +65,7 @@ namespace xs
 
     private:
 
-        poller_base_t *poller;
+        io_thread_t *io_thread;
 
         io_object_t (const io_object_t&);
         const io_object_t &operator = (const io_object_t&);
diff --git a/src/poller_base.cpp b/src/io_thread.cpp
index 913a8d7..d6dca8c 100644
--- a/src/poller_base.cpp
+++ b/src/io_thread.cpp
@@ -18,7 +18,7 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 #include "err.hpp"
 
 #include "select.hpp"
@@ -27,9 +27,9 @@
 #include "devpoll.hpp"
 #include "kqueue.hpp"
 
-xs::poller_base_t *xs::poller_base_t::create (xs::ctx_t *ctx_, uint32_t tid_)
+xs::io_thread_t *xs::io_thread_t::create (xs::ctx_t *ctx_, uint32_t tid_)
 {
-    poller_base_t *result;
+    io_thread_t *result;
 #if defined XS_HAVE_SELECT
     result = new (std::nothrow) select_t (ctx_, tid_);
 #elif defined XS_HAVE_POLL
@@ -45,45 +45,45 @@ xs::poller_base_t *xs::poller_base_t::create (xs::ctx_t *ctx_, uint32_t tid_)
     return result;
 }
 
-xs::poller_base_t::poller_base_t (xs::ctx_t *ctx_, uint32_t tid_) :
+xs::io_thread_t::io_thread_t (xs::ctx_t *ctx_, uint32_t tid_) :
     object_t (ctx_, tid_)
 {
 }
 
-xs::poller_base_t::~poller_base_t ()
+xs::io_thread_t::~io_thread_t ()
 {
 }
 
-void xs::poller_base_t::start ()
+void xs::io_thread_t::start ()
 {
     mailbox_handle = add_fd (mailbox.get_fd (), this);
     set_pollin (mailbox_handle);
     xstart ();
 }
 
-void xs::poller_base_t::stop ()
+void xs::io_thread_t::stop ()
 {
     //  Ask the I/O thread to stop.
     send_stop ();
 }
 
-void xs::poller_base_t::process_stop ()
+void xs::io_thread_t::process_stop ()
 {
     rm_fd (mailbox_handle);
     xstop ();
 }
 
-xs::mailbox_t *xs::poller_base_t::get_mailbox ()
+xs::mailbox_t *xs::io_thread_t::get_mailbox ()
 {
     return &mailbox;
 }
 
-int xs::poller_base_t::get_load ()
+int xs::io_thread_t::get_load ()
 {
     return load.get ();
 }
 
-void xs::poller_base_t::adjust_load (int amount_)
+void xs::io_thread_t::adjust_load (int amount_)
 {
     if (amount_ > 0)
         load.add (amount_);
@@ -91,7 +91,7 @@ void xs::poller_base_t::adjust_load (int amount_)
         load.sub (-amount_);
 }
 
-xs::handle_t xs::poller_base_t::add_timer (int timeout_, i_poll_events *sink_)
+xs::handle_t xs::io_thread_t::add_timer (int timeout_, i_poll_events *sink_)
 {
     uint64_t expiration = clock.now_ms () + timeout_;
     timer_info_t info = {sink_, timers_t::iterator ()};
@@ -101,13 +101,13 @@ xs::handle_t xs::poller_base_t::add_timer (int timeout_, i_poll_events *sink_)
     return (handle_t) &(it->second);
 }
 
-void xs::poller_base_t::rm_timer (handle_t handle_)
+void xs::io_thread_t::rm_timer (handle_t handle_)
 {
     timer_info_t *info = (timer_info_t*) handle_;
     timers.erase (info->self);
 }
 
-uint64_t xs::poller_base_t::execute_timers ()
+uint64_t xs::io_thread_t::execute_timers ()
 {
     //  Fast track.
     if (timers.empty ())
@@ -140,7 +140,7 @@ uint64_t xs::poller_base_t::execute_timers ()
     return 0;
 }
 
-void xs::poller_base_t::in_event (fd_t fd_)
+void xs::io_thread_t::in_event (fd_t fd_)
 {
     //  TODO: Do we want to limit number of commands I/O thread can
     //  process in a single go?
@@ -161,13 +161,13 @@ void xs::poller_base_t::in_event (fd_t fd_)
     }
 }
 
-void xs::poller_base_t::out_event (fd_t fd_)
+void xs::io_thread_t::out_event (fd_t fd_)
 {
     //  We are never polling for POLLOUT here. This function is never called.
     xs_assert (false);
 }
 
-void xs::poller_base_t::timer_event (handle_t handle_)
+void xs::io_thread_t::timer_event (handle_t handle_)
 {
     //  No timers here. This function is never called.
     xs_assert (false);
diff --git a/src/poller_base.hpp b/src/io_thread.hpp
index 2388fad..689b851 100644
--- a/src/poller_base.hpp
+++ b/src/io_thread.hpp
@@ -18,8 +18,8 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#ifndef __XS_POLLER_BASE_HPP_INCLUDED__
-#define __XS_POLLER_BASE_HPP_INCLUDED__
+#ifndef __XS_IO_THREAD_HPP_INCLUDED__
+#define __XS_IO_THREAD_HPP_INCLUDED__
 
 #include <map>
 
@@ -54,23 +54,23 @@ namespace xs
         virtual void timer_event (handle_t handle_) = 0;
     };
 
-    class poller_base_t : public object_t, public i_poll_events
+    class io_thread_t : public object_t, public i_poll_events
     {
     public:
 
-        //  Create optimal poller mechanism for this environment.
-        static poller_base_t *create (xs::ctx_t *ctx_, uint32_t tid_);
+        //  Create optimal polling mechanism for this environment.
+        static io_thread_t *create (xs::ctx_t *ctx_, uint32_t tid_);
 
-        virtual ~poller_base_t ();
+        virtual ~io_thread_t ();
 
-        //  Returns load of the poller. Note that this function can be
+        //  Returns load of the I/O thread. Note that this function can be
         //  invoked from a different thread!
         int get_load ();
 
         void start ();
         void stop ();
 
-        //  Returns mailbox associated with this I/O poller.
+        //  Returns mailbox associated with this I/O thread.
         mailbox_t *get_mailbox ();
 
         virtual handle_t add_fd (fd_t fd_, xs::i_poll_events *events_) = 0;
@@ -96,9 +96,9 @@ namespace xs
 
     protected:
 
-        poller_base_t (xs::ctx_t *ctx_, uint32_t tid_);
+        io_thread_t (xs::ctx_t *ctx_, uint32_t tid_);
 
-        //  Called by individual poller implementations to manage the load.
+        //  Called by individual io_thread implementations to manage the load.
         void adjust_load (int amount_);
 
         //  Executes any timers that are due. Returns number of milliseconds
@@ -121,7 +121,7 @@ namespace xs
         typedef std::multimap <uint64_t, timer_info_t> timers_t;
         timers_t timers;
 
-        //  Load of the poller. Currently the number of file descriptors
+        //  Load of the I/O thread. Currently the number of file descriptors
         //  registered.
         atomic_counter_t load;
 
@@ -131,8 +131,8 @@ namespace xs
         //  Handle associated with mailbox' file descriptor.
         handle_t mailbox_handle;
 
-        poller_base_t (const poller_base_t&);
-        const poller_base_t &operator = (const poller_base_t&);
+        io_thread_t (const io_thread_t&);
+        const io_thread_t &operator = (const io_thread_t&);
     };
 
 }
diff --git a/src/ipc_connecter.cpp b/src/ipc_connecter.cpp
index b65887a..f6a01c3 100644
--- a/src/ipc_connecter.cpp
+++ b/src/ipc_connecter.cpp
@@ -26,7 +26,7 @@
 #include <string>
 
 #include "stream_engine.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 #include "platform.hpp"
 #include "random.hpp"
 #include "err.hpp"
@@ -37,7 +37,7 @@
 #include <sys/socket.h>
 #include <sys/un.h>
 
-xs::ipc_connecter_t::ipc_connecter_t (class poller_base_t *io_thread_,
+xs::ipc_connecter_t::ipc_connecter_t (class io_thread_t *io_thread_,
       class session_base_t *session_, const options_t &options_,
       const char *address_, bool wait_) :
     own_t (io_thread_, options_),
diff --git a/src/ipc_connecter.hpp b/src/ipc_connecter.hpp
index 46e260c..e598393 100644
--- a/src/ipc_connecter.hpp
+++ b/src/ipc_connecter.hpp
@@ -34,7 +34,7 @@
 namespace xs
 {
 
-    class poller_base_t;
+    class io_thread_t;
     class session_base_t;
 
     class ipc_connecter_t : public own_t, public io_object_t
@@ -43,7 +43,7 @@ namespace xs
 
         //  If 'delay' is true connecter first waits for a while, then starts
         //  connection process.
-        ipc_connecter_t (xs::poller_base_t *io_thread_,
+        ipc_connecter_t (xs::io_thread_t *io_thread_,
             xs::session_base_t *session_, const options_t &options_,
             const char *address_, bool delay_);
         ~ipc_connecter_t ();
@@ -94,7 +94,7 @@ namespace xs
         fd_t s;
 
         //  Handle corresponding to the listening socket or NULL if the socket
-        //  is not registered with the poller.
+        //  is not registered with the io_thread.
         handle_t handle;
 
         //  If true, connecter is waiting a while before trying to connect.
diff --git a/src/ipc_listener.cpp b/src/ipc_listener.cpp
index bd55cc7..db49528 100644
--- a/src/ipc_listener.cpp
+++ b/src/ipc_listener.cpp
@@ -28,7 +28,7 @@
 
 #include "stream_engine.hpp"
 #include "ipc_address.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 #include "session_base.hpp"
 #include "config.hpp"
 #include "err.hpp"
@@ -39,7 +39,7 @@
 #include <fcntl.h>
 #include <sys/un.h>
 
-xs::ipc_listener_t::ipc_listener_t (poller_base_t *io_thread_,
+xs::ipc_listener_t::ipc_listener_t (io_thread_t *io_thread_,
       socket_base_t *socket_, const options_t &options_) :
     own_t (io_thread_, options_),
     io_object_t (io_thread_),
@@ -83,7 +83,7 @@ void xs::ipc_listener_t::in_event (fd_t fd_)
 
     //  Choose I/O thread to run connecter in. Given that we are already
     //  running in an I/O thread, there must be at least one available.
-    poller_base_t *io_thread = choose_io_thread (options.affinity);
+    io_thread_t *io_thread = choose_io_thread (options.affinity);
     xs_assert (io_thread);
 
     //  Create and launch a session object. 
diff --git a/src/ipc_listener.hpp b/src/ipc_listener.hpp
index 24b96fb..b599bff 100644
--- a/src/ipc_listener.hpp
+++ b/src/ipc_listener.hpp
@@ -35,14 +35,14 @@
 namespace xs
 {
 
-    class poller_base_t;
+    class io_thread_t;
     class socket_base_t;
 
     class ipc_listener_t : public own_t, public io_object_t
     {
     public:
 
-        ipc_listener_t (xs::poller_base_t *io_thread_,
+        ipc_listener_t (xs::io_thread_t *io_thread_,
             xs::socket_base_t *socket_, const options_t &options_);
         ~ipc_listener_t ();
 
diff --git a/src/kqueue.cpp b/src/kqueue.cpp
index 6a193df..1a0ee4d 100644
--- a/src/kqueue.cpp
+++ b/src/kqueue.cpp
@@ -45,7 +45,7 @@
 #endif
 
 xs::kqueue_t::kqueue_t (xs::ctx_t *ctx_, uint32_t tid_) :
-    poller_base_t (ctx_, tid_),
+    io_thread_t (ctx_, tid_),
     stopping (false)
 {
     //  Create event queue
diff --git a/src/kqueue.hpp b/src/kqueue.hpp
index f3350b9..dea84ac 100644
--- a/src/kqueue.hpp
+++ b/src/kqueue.hpp
@@ -29,7 +29,7 @@
 
 #include "fd.hpp"
 #include "thread.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 
 namespace xs
 {
@@ -39,14 +39,14 @@ namespace xs
     //  Implements socket polling mechanism using the BSD-specific
     //  kqueue interface.
 
-    class kqueue_t : public poller_base_t
+    class kqueue_t : public io_thread_t
     {
     public:
 
         kqueue_t (xs::ctx_t *ctx_, uint32_t tid_);
         ~kqueue_t ();
 
-        //  "poller" concept.
+        //  Implementation of virtual functions from io_thread_t.
         handle_t add_fd (fd_t fd_, xs::i_poll_events *events_);
         void rm_fd (handle_t handle_);
         void set_pollin (handle_t handle_);
diff --git a/src/monitor.cpp b/src/monitor.cpp
index 14a31f2..b29c874 100644
--- a/src/monitor.cpp
+++ b/src/monitor.cpp
@@ -19,12 +19,12 @@
 */
 
 #include "monitor.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 #include "options.hpp"
 #include "random.hpp"
 #include "err.hpp"
 
-xs::monitor_t::monitor_t (xs::poller_base_t *io_thread_) :
+xs::monitor_t::monitor_t (xs::io_thread_t *io_thread_) :
     own_t (io_thread_, options_t ()),
     io_object_t (io_thread_),
     timer (NULL)
diff --git a/src/monitor.hpp b/src/monitor.hpp
index 91d441a..db6f74b 100644
--- a/src/monitor.hpp
+++ b/src/monitor.hpp
@@ -30,14 +30,14 @@
 namespace xs
 {
 
-    class poller_base_t;
+    class io_thread_t;
     class socket_base_t;
 
     class monitor_t : public own_t, public io_object_t
     {
     public:
 
-        monitor_t (xs::poller_base_t *io_thread_);
+        monitor_t (xs::io_thread_t *io_thread_);
         ~monitor_t ();
 
         void start ();
@@ -51,7 +51,7 @@ namespace xs
         void process_plug ();
         void process_stop ();
 
-        //  Events from the poller.
+        //  Events from the I/O thread.
         void timer_event (handle_t handle_);
 
         //  Actual monitoring data to send and the related critical section.
diff --git a/src/object.cpp b/src/object.cpp
index df279f5..2d1f5aa 100644
--- a/src/object.cpp
+++ b/src/object.cpp
@@ -26,7 +26,7 @@
 #include "ctx.hpp"
 #include "err.hpp"
 #include "pipe.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 #include "session_base.hpp"
 #include "socket_base.hpp"
 
@@ -149,7 +149,7 @@ void xs::object_t::destroy_socket (socket_base_t *socket_)
     ctx->destroy_socket (socket_);
 }
 
-xs::poller_base_t *xs::object_t::choose_io_thread (uint64_t affinity_)
+xs::io_thread_t *xs::object_t::choose_io_thread (uint64_t affinity_)
 {
     return ctx->choose_io_thread (affinity_);
 }
diff --git a/src/object.hpp b/src/object.hpp
index 14dad49..b1bc0c3 100644
--- a/src/object.hpp
+++ b/src/object.hpp
@@ -34,7 +34,7 @@ namespace xs
     class pipe_t;
     class socket_base_t;
     class session_base_t;
-    class poller_base_t;
+    class io_thread_t;
     class own_t;
 
     //  Base class for all objects that participate in inter-thread
@@ -62,7 +62,7 @@ namespace xs
         void destroy_socket (xs::socket_base_t *socket_);
 
         //  Chooses least loaded I/O thread.
-        xs::poller_base_t *choose_io_thread (uint64_t affinity_);
+        xs::io_thread_t *choose_io_thread (uint64_t affinity_);
 
         //  Logging related functions.
         void log (int sid_, const char *text_);
diff --git a/src/own.cpp b/src/own.cpp
index 3047d7b..a60d9d0 100644
--- a/src/own.cpp
+++ b/src/own.cpp
@@ -20,7 +20,7 @@
 
 #include "own.hpp"
 #include "err.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 
 xs::own_t::own_t (class ctx_t *parent_, uint32_t tid_) :
     object_t (parent_, tid_),
@@ -32,7 +32,7 @@ xs::own_t::own_t (class ctx_t *parent_, uint32_t tid_) :
 {
 }
 
-xs::own_t::own_t (poller_base_t *io_thread_, const options_t &options_) :
+xs::own_t::own_t (io_thread_t *io_thread_, const options_t &options_) :
     object_t (io_thread_),
     options (options_),
     terminating (false),
diff --git a/src/own.hpp b/src/own.hpp
index de0320a..d0afd62 100644
--- a/src/own.hpp
+++ b/src/own.hpp
@@ -33,7 +33,7 @@ namespace xs
 {
 
     class ctx_t;
-    class poller_base_t;
+    class io_thread_t;
 
     //  Base class for objects forming a part of ownership hierarchy.
     //  It handles initialisation and destruction of such objects.
@@ -50,7 +50,7 @@ namespace xs
         own_t (xs::ctx_t *parent_, uint32_t tid_);
 
         //  The object is living within I/O thread.
-        own_t (xs::poller_base_t *io_thread_, const options_t &options_);
+        own_t (xs::io_thread_t *io_thread_, const options_t &options_);
 
         //  When another owned object wants to send command to this object
         //  it calls this function to let it know it should not shut down
diff --git a/src/pair.cpp b/src/pair.cpp
index c35084f..dd14d8d 100644
--- a/src/pair.cpp
+++ b/src/pair.cpp
@@ -117,7 +117,7 @@ bool xs::pair_t::xhas_out ()
     return result;
 }
 
-xs::pair_session_t::pair_session_t (poller_base_t *io_thread_, bool connect_,
+xs::pair_session_t::pair_session_t (io_thread_t *io_thread_, bool connect_,
       socket_base_t *socket_, const options_t &options_,
       const char *protocol_, const char *address_) :
     session_base_t (io_thread_, connect_, socket_, options_, protocol_,
diff --git a/src/pair.hpp b/src/pair.hpp
index 658e8e9..8ae3acf 100644
--- a/src/pair.hpp
+++ b/src/pair.hpp
@@ -63,7 +63,7 @@ namespace xs
     {
     public:
 
-        pair_session_t (xs::poller_base_t *io_thread_, bool connect_,
+        pair_session_t (xs::io_thread_t *io_thread_, bool connect_,
             socket_base_t *socket_, const options_t &options_,
             const char *protocol_, const char *address_);
         ~pair_session_t ();
diff --git a/src/pgm_receiver.cpp b/src/pgm_receiver.cpp
index 3b29197..b2cc513 100644
--- a/src/pgm_receiver.cpp
+++ b/src/pgm_receiver.cpp
@@ -37,7 +37,7 @@
 #include "wire.hpp"
 #include "err.hpp"
 
-xs::pgm_receiver_t::pgm_receiver_t (class poller_base_t *parent_, 
+xs::pgm_receiver_t::pgm_receiver_t (class io_thread_t *parent_, 
       const options_t &options_) :
     io_object_t (parent_),
     pgm_socket (true, options_),
@@ -60,7 +60,7 @@ int xs::pgm_receiver_t::init (bool udp_encapsulation_, const char *network_)
     return pgm_socket.init (udp_encapsulation_, network_);
 }
 
-void xs::pgm_receiver_t::plug (poller_base_t *io_thread_,
+void xs::pgm_receiver_t::plug (io_thread_t *io_thread_,
     session_base_t *session_)
 {
     //  Retrieve PGM fds and start polling.
diff --git a/src/pgm_receiver.hpp b/src/pgm_receiver.hpp
index 952265e..b8390c1 100644
--- a/src/pgm_receiver.hpp
+++ b/src/pgm_receiver.hpp
@@ -43,7 +43,7 @@
 namespace xs
 {
 
-    class poller_base_t;
+    class io_thread_t;
     class session_base_t;
 
     class pgm_receiver_t : public io_object_t, public i_engine
@@ -51,13 +51,13 @@ namespace xs
     
     public:
 
-        pgm_receiver_t (xs::poller_base_t *parent_, const options_t &options_);
+        pgm_receiver_t (xs::io_thread_t *parent_, const options_t &options_);
         ~pgm_receiver_t ();
 
         int init (bool udp_encapsulation_, const char *network_);
 
         //  i_engine interface implementation.
-        void plug (xs::poller_base_t *io_thread_,
+        void plug (xs::io_thread_t *io_thread_,
             xs::session_base_t *session_);
         void unplug ();
         void terminate ();
diff --git a/src/pgm_sender.cpp b/src/pgm_sender.cpp
index 20d3dba..fe57d4d 100644
--- a/src/pgm_sender.cpp
+++ b/src/pgm_sender.cpp
@@ -37,7 +37,7 @@
 #include "wire.hpp"
 #include "stdint.hpp"
 
-xs::pgm_sender_t::pgm_sender_t (poller_base_t *parent_, 
+xs::pgm_sender_t::pgm_sender_t (io_thread_t *parent_, 
       const options_t &options_) :
     io_object_t (parent_),
     encoder (0),
@@ -64,7 +64,7 @@ int xs::pgm_sender_t::init (bool udp_encapsulation_, const char *network_)
     return rc;
 }
 
-void xs::pgm_sender_t::plug (poller_base_t *io_thread_,
+void xs::pgm_sender_t::plug (io_thread_t *io_thread_,
     session_base_t *session_)
 {
     //  Alocate 2 fds for PGM socket.
@@ -75,7 +75,7 @@ void xs::pgm_sender_t::plug (poller_base_t *io_thread_,
 
     encoder.set_session (session_);
 
-    //  Fill fds from PGM transport and add them to the poller.
+    //  Fill fds from PGM transport and add them to the I/O thread.
     pgm_socket.get_sender_fds (&downlink_socket_fd, &uplink_socket_fd,
         &rdata_notify_fd, &pending_notify_fd);
 
@@ -204,7 +204,7 @@ void xs::pgm_sender_t::out_event (fd_t fd_)
 
 void xs::pgm_sender_t::timer_event (handle_t handle_)
 {
-    //  Timer cancels on return by poller_base.
+    //  Timer cancels on return by io_thread.
     if (handle_ == rx_timer) {
         rx_timer = NULL;
         in_event (retired_fd);
diff --git a/src/pgm_sender.hpp b/src/pgm_sender.hpp
index be6476b..000f5ba 100644
--- a/src/pgm_sender.hpp
+++ b/src/pgm_sender.hpp
@@ -41,7 +41,7 @@
 namespace xs
 {
 
-    class poller_base_t;
+    class io_thread_t;
     class session_base_t;
 
     class pgm_sender_t : public io_object_t, public i_engine
@@ -49,13 +49,13 @@ namespace xs
 
     public:
 
-        pgm_sender_t (xs::poller_base_t *parent_, const options_t &options_);
+        pgm_sender_t (xs::io_thread_t *parent_, const options_t &options_);
         ~pgm_sender_t ();
 
         int init (bool udp_encapsulation_, const char *network_);
 
         //  i_engine interface implementation.
-        void plug (xs::poller_base_t *io_thread_,
+        void plug (xs::io_thread_t *io_thread_,
             xs::session_base_t *session_);
         void unplug ();
         void terminate ();
diff --git a/src/poll.cpp b/src/poll.cpp
index 622a0ea..2cb7669 100644
--- a/src/poll.cpp
+++ b/src/poll.cpp
@@ -33,7 +33,7 @@
 #include "config.hpp"
 
 xs::poll_t::poll_t (xs::ctx_t *ctx_, uint32_t tid_) :
-    poller_base_t (ctx_, tid_),
+    io_thread_t (ctx_, tid_),
     retired (false),
     stopping (false)
 {
diff --git a/src/poll.hpp b/src/poll.hpp
index 3d5157e..ec06671 100644
--- a/src/poll.hpp
+++ b/src/poll.hpp
@@ -32,7 +32,7 @@
 
 #include "fd.hpp"
 #include "thread.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 
 namespace xs
 {
@@ -42,14 +42,14 @@ namespace xs
     //  Implements socket polling mechanism using the POSIX.1-2001
     //  poll() system call.
 
-    class poll_t : public poller_base_t
+    class poll_t : public io_thread_t
     {
     public:
 
         poll_t (xs::ctx_t *ctx_, uint32_t tid_);
         ~poll_t ();
 
-        //  "poller" concept.
+        //  Implementation of virtual functions from io_thread_t.
         handle_t add_fd (fd_t fd_, xs::i_poll_events *events_);
         void rm_fd (handle_t handle_);
         void set_pollin (handle_t handle_);
diff --git a/src/pub.cpp b/src/pub.cpp
index db285b8..aa0ed8e 100644
--- a/src/pub.cpp
+++ b/src/pub.cpp
@@ -44,7 +44,7 @@ bool xs::pub_t::xhas_in ()
     return false;
 }
 
-xs::pub_session_t::pub_session_t (poller_base_t *io_thread_, bool connect_,
+xs::pub_session_t::pub_session_t (io_thread_t *io_thread_, bool connect_,
       socket_base_t *socket_, const options_t &options_,
       const char *protocol_, const char *address_) :
     xpub_session_t (io_thread_, connect_, socket_, options_, protocol_,
diff --git a/src/pub.hpp b/src/pub.hpp
index 45b510e..49aecc0 100644
--- a/src/pub.hpp
+++ b/src/pub.hpp
@@ -28,7 +28,7 @@ namespace xs
 {
 
     class ctx_t;
-    class poller_base_t;
+    class io_thread_t;
     class socket_base_t;
     class msg_t;
 
@@ -53,7 +53,7 @@ namespace xs
     {
     public:
 
-        pub_session_t (xs::poller_base_t *io_thread_, bool connect_,
+        pub_session_t (xs::io_thread_t *io_thread_, bool connect_,
             xs::socket_base_t *socket_, const options_t &options_,
             const char *protocol_, const char *address_);
         ~pub_session_t ();
diff --git a/src/pull.cpp b/src/pull.cpp
index 923c85b..e168c03 100644
--- a/src/pull.cpp
+++ b/src/pull.cpp
@@ -60,7 +60,7 @@ bool xs::pull_t::xhas_in ()
     return fq.has_in ();
 }
 
-xs::pull_session_t::pull_session_t (poller_base_t *io_thread_, bool connect_,
+xs::pull_session_t::pull_session_t (io_thread_t *io_thread_, bool connect_,
       socket_base_t *socket_, const options_t &options_,
       const char *protocol_, const char *address_) :
     session_base_t (io_thread_, connect_, socket_, options_, protocol_,
diff --git a/src/pull.hpp b/src/pull.hpp
index a02ef2d..29ca4d9 100644
--- a/src/pull.hpp
+++ b/src/pull.hpp
@@ -32,7 +32,7 @@ namespace xs
     class ctx_t;
     class pipe_t;
     class msg_t;
-    class poller_base_t;
+    class io_thread_t;
 
     class pull_t :
         public socket_base_t
@@ -65,7 +65,7 @@ namespace xs
     {
     public:
 
-        pull_session_t (xs::poller_base_t *io_thread_, bool connect_,
+        pull_session_t (xs::io_thread_t *io_thread_, bool connect_,
             socket_base_t *socket_, const options_t &options_,
             const char *protocol_, const char *address_);
         ~pull_session_t ();
diff --git a/src/push.cpp b/src/push.cpp
index ffc2d6e..45f0c62 100644
--- a/src/push.cpp
+++ b/src/push.cpp
@@ -60,7 +60,7 @@ bool xs::push_t::xhas_out ()
     return lb.has_out ();
 }
 
-xs::push_session_t::push_session_t (poller_base_t *io_thread_, bool connect_,
+xs::push_session_t::push_session_t (io_thread_t *io_thread_, bool connect_,
       socket_base_t *socket_, const options_t &options_,
       const char *protocol_, const char *address_) :
     session_base_t (io_thread_, connect_, socket_, options_, protocol_,
diff --git a/src/push.hpp b/src/push.hpp
index f6102c6..85c2279 100644
--- a/src/push.hpp
+++ b/src/push.hpp
@@ -32,7 +32,7 @@ namespace xs
     class ctx_t;
     class pipe_t;
     class msg_t;
-    class poller_base_t;
+    class io_thread_t;
 
     class push_t :
         public socket_base_t
@@ -64,7 +64,7 @@ namespace xs
     {
     public:
 
-        push_session_t (xs::poller_base_t *io_thread_, bool connect_,
+        push_session_t (xs::io_thread_t *io_thread_, bool connect_,
             socket_base_t *socket_, const options_t &options_,
             const char *protocol_, const char *address_);
         ~push_session_t ();
diff --git a/src/reaper.cpp b/src/reaper.cpp
index ffce0a9..7ce9e04 100644
--- a/src/reaper.cpp
+++ b/src/reaper.cpp
@@ -27,16 +27,16 @@ xs::reaper_t::reaper_t (class ctx_t *ctx_, uint32_t tid_) :
     sockets (0),
     terminating (false)
 {
-    poller = poller_base_t::create (ctx_, tid_);
-    xs_assert (poller);
+    io_thread = io_thread_t::create (ctx_, tid_);
+    xs_assert (io_thread);
 
-    mailbox_handle = poller->add_fd (mailbox.get_fd (), this);
-    poller->set_pollin (mailbox_handle);
+    mailbox_handle = io_thread->add_fd (mailbox.get_fd (), this);
+    io_thread->set_pollin (mailbox_handle);
 }
 
 xs::reaper_t::~reaper_t ()
 {
-    delete poller;
+    delete io_thread;
 }
 
 xs::mailbox_t *xs::reaper_t::get_mailbox ()
@@ -47,7 +47,7 @@ xs::mailbox_t *xs::reaper_t::get_mailbox ()
 void xs::reaper_t::start ()
 {
     //  Start the thread.
-    poller->start ();
+    io_thread->start ();
 }
 
 void xs::reaper_t::stop ()
@@ -90,15 +90,15 @@ void xs::reaper_t::process_stop ()
     //  If there are no sockets being reaped finish immediately.
     if (!sockets) {
         send_done ();
-        poller->rm_fd (mailbox_handle);
-        poller->stop ();
+        io_thread->rm_fd (mailbox_handle);
+        io_thread->stop ();
     }
 }
 
 void xs::reaper_t::process_reap (socket_base_t *socket_)
 {
-    //  Add the socket to the poller.
-    socket_->start_reaping (poller);
+    //  Add the socket to the I/O thread.
+    socket_->start_reaping (io_thread);
 
     ++sockets;
 }
@@ -111,7 +111,7 @@ void xs::reaper_t::process_reaped ()
     //  finish immediately.
     if (!sockets && terminating) {
         send_done ();
-        poller->rm_fd (mailbox_handle);
-        poller->stop ();
+        io_thread->rm_fd (mailbox_handle);
+        io_thread->stop ();
     }
 }
diff --git a/src/reaper.hpp b/src/reaper.hpp
index bc40fac..0e7618b 100644
--- a/src/reaper.hpp
+++ b/src/reaper.hpp
@@ -23,7 +23,7 @@
 
 #include "object.hpp"
 #include "mailbox.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 
 namespace xs
 {
@@ -61,8 +61,8 @@ namespace xs
         //  Handle associated with mailbox' file descriptor.
         handle_t mailbox_handle;
 
-        //  I/O multiplexing is performed using a poller object.
-        poller_base_t *poller;
+        //  I/O multiplexing is performed using an io_thread object.
+        io_thread_t *io_thread;
 
         //  Number of sockets being reaped at the moment.
         int sockets;
diff --git a/src/rep.cpp b/src/rep.cpp
index 5e5e415..6454b57 100644
--- a/src/rep.cpp
+++ b/src/rep.cpp
@@ -112,7 +112,7 @@ bool xs::rep_t::xhas_out ()
     return xrep_t::xhas_out ();
 }
 
-xs::rep_session_t::rep_session_t (poller_base_t *io_thread_, bool connect_,
+xs::rep_session_t::rep_session_t (io_thread_t *io_thread_, bool connect_,
       socket_base_t *socket_, const options_t &options_,
       const char *protocol_, const char *address_) :
     xrep_session_t (io_thread_, connect_, socket_, options_, protocol_,
diff --git a/src/rep.hpp b/src/rep.hpp
index 2cd3931..0b608ee 100644
--- a/src/rep.hpp
+++ b/src/rep.hpp
@@ -29,7 +29,7 @@ namespace xs
 
     class ctx_t;
     class msg_t;
-    class poller_base_t;
+    class io_thread_t;
     class socket_base_t;
 
     class rep_t : public xrep_t
@@ -64,7 +64,7 @@ namespace xs
     {
     public:
 
-        rep_session_t (xs::poller_base_t *io_thread_, bool connect_,
+        rep_session_t (xs::io_thread_t *io_thread_, bool connect_,
             xs::socket_base_t *socket_, const options_t &options_,
             const char *protocol_, const char *address_);
         ~rep_session_t ();
diff --git a/src/req.cpp b/src/req.cpp
index 6e9867c..af6c8cd 100644
--- a/src/req.cpp
+++ b/src/req.cpp
@@ -137,7 +137,7 @@ bool xs::req_t::xhas_out ()
     return xreq_t::xhas_out ();
 }
 
-xs::req_session_t::req_session_t (poller_base_t *io_thread_, bool connect_,
+xs::req_session_t::req_session_t (io_thread_t *io_thread_, bool connect_,
       socket_base_t *socket_, const options_t &options_,
       const char *protocol_, const char *address_) :
     xreq_session_t (io_thread_, connect_, socket_, options_, protocol_,
diff --git a/src/req.hpp b/src/req.hpp
index 8da789f..46015e8 100644
--- a/src/req.hpp
+++ b/src/req.hpp
@@ -31,7 +31,7 @@ namespace xs
 
     class ctx_t;
     class msg_t;
-    class poller_base_t;
+    class io_thread_t;
     class socket_base_t;
 
     class req_t : public xreq_t
@@ -65,7 +65,7 @@ namespace xs
     {
     public:
 
-        req_session_t (xs::poller_base_t *io_thread_, bool connect_,
+        req_session_t (xs::io_thread_t *io_thread_, bool connect_,
             xs::socket_base_t *socket_, const options_t &options_,
             const char *protocol_, const char *address_);
         ~req_session_t ();
diff --git a/src/select.cpp b/src/select.cpp
index 1b63685..af5f0f7 100644
--- a/src/select.cpp
+++ b/src/select.cpp
@@ -44,7 +44,7 @@
 #include "config.hpp"
 
 xs::select_t::select_t (xs::ctx_t *ctx_, uint32_t tid_) :
-    poller_base_t (ctx_, tid_),
+    io_thread_t (ctx_, tid_),
     maxfd (retired_fd),
     retired (false),
     stopping (false)
diff --git a/src/select.hpp b/src/select.hpp
index 283cc52..b1b96ef 100644
--- a/src/select.hpp
+++ b/src/select.hpp
@@ -42,7 +42,7 @@
 
 #include "fd.hpp"
 #include "thread.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 
 namespace xs
 {
@@ -52,14 +52,14 @@ namespace xs
     //  Implements socket polling mechanism using POSIX.1-2001 select()
     //  function.
 
-    class select_t : public poller_base_t
+    class select_t : public io_thread_t
     {
     public:
 
         select_t (xs::ctx_t *ctx_, uint32_t tid_);
         ~select_t ();
 
-        //  "poller" concept.
+        //  Implementation of virtual functions from io_thread_t.
         handle_t add_fd (fd_t fd_, xs::i_poll_events *events_);
         void rm_fd (handle_t handle_);
         void set_pollin (handle_t handle_);
diff --git a/src/session_base.cpp b/src/session_base.cpp
index 168501c..efc4f8b 100644
--- a/src/session_base.cpp
+++ b/src/session_base.cpp
@@ -43,7 +43,7 @@
 #include "pull.hpp"
 #include "pair.hpp"
 
-xs::session_base_t *xs::session_base_t::create (class poller_base_t *io_thread_,
+xs::session_base_t *xs::session_base_t::create (class io_thread_t *io_thread_,
     bool connect_, class socket_base_t *socket_, const options_t &options_,
     const char *protocol_, const char *address_)
 {
@@ -100,7 +100,7 @@ xs::session_base_t *xs::session_base_t::create (class poller_base_t *io_thread_,
     return s;
 }
 
-xs::session_base_t::session_base_t (class poller_base_t *io_thread_,
+xs::session_base_t::session_base_t (class io_thread_t *io_thread_,
       bool connect_, class socket_base_t *socket_, const options_t &options_,
       const char *protocol_, const char *address_) :
     own_t (io_thread_, options_),
@@ -387,7 +387,7 @@ void xs::session_base_t::start_connecting (bool wait_)
 
     //  Choose I/O thread to run connecter in. Given that we are already
     //  running in an I/O thread, there must be at least one available.
-    poller_base_t *io_thread = choose_io_thread (options.affinity);
+    io_thread_t *io_thread = choose_io_thread (options.affinity);
     xs_assert (io_thread);
 
     //  Create the connecter object.
diff --git a/src/session_base.hpp b/src/session_base.hpp
index 6a461d8..45ad8f8 100644
--- a/src/session_base.hpp
+++ b/src/session_base.hpp
@@ -33,7 +33,7 @@ namespace xs
 {
 
     class pipe_t;
-    class poller_base_t;
+    class io_thread_t;
     class socket_base_t;
     struct i_engine;
 
@@ -45,7 +45,7 @@ namespace xs
     public:
 
         //  Create a session of the particular type.
-        static session_base_t *create (xs::poller_base_t *io_thread_,
+        static session_base_t *create (xs::io_thread_t *io_thread_,
             bool connect_, xs::socket_base_t *socket_,
             const options_t &options_, const char *protocol_,
             const char *address_);
@@ -67,7 +67,7 @@ namespace xs
 
     protected:
 
-        session_base_t (xs::poller_base_t *io_thread_, bool connect_,
+        session_base_t (xs::io_thread_t *io_thread_, bool connect_,
             xs::socket_base_t *socket_, const options_t &options_,
             const char *protocol_, const char *address_);
         ~session_base_t ();
@@ -116,7 +116,7 @@ namespace xs
 
         //  I/O thread the session is living in. It will be used to plug in
         //  the engines into the same thread.
-        xs::poller_base_t *io_thread;
+        xs::io_thread_t *io_thread;
 
         //  If true, identity is to be sent/recvd from the network.
         bool send_identity;
diff --git a/src/socket_base.cpp b/src/socket_base.cpp
index 492d027..7ab00ea 100644
--- a/src/socket_base.cpp
+++ b/src/socket_base.cpp
@@ -39,7 +39,7 @@
 #include "tcp_listener.hpp"
 #include "ipc_listener.hpp"
 #include "tcp_connecter.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 #include "session_base.hpp"
 #include "config.hpp"
 #include "clock.hpp"
@@ -338,7 +338,7 @@ int xs::socket_base_t::bind (const char *addr_)
 
     //  Remaining trasnports require to be run in an I/O thread, so at this
     //  point we'll choose one.
-    poller_base_t *io_thread = choose_io_thread (options.affinity);
+    io_thread_t *io_thread = choose_io_thread (options.affinity);
     if (!io_thread) {
         errno = EMTHREAD;
         return -1;
@@ -449,7 +449,7 @@ int xs::socket_base_t::connect (const char *addr_)
     }
 
     //  Choose the I/O thread to run the session in.
-    poller_base_t *io_thread = choose_io_thread (options.affinity);
+    io_thread_t *io_thread = choose_io_thread (options.affinity);
     if (!io_thread) {
         errno = EMTHREAD;
         return -1;
@@ -667,12 +667,12 @@ bool xs::socket_base_t::has_out ()
     return ret;
 }
 
-void xs::socket_base_t::start_reaping (poller_base_t *poller_)
+void xs::socket_base_t::start_reaping (io_thread_t *io_thread_)
 {
     //  Plug the socket to the reaper thread.
-    poller = poller_;
-    handle = poller->add_fd (mailbox.get_fd (), this);
-    poller->set_pollin (handle);
+    io_thread = io_thread_;
+    handle = io_thread->add_fd (mailbox.get_fd (), this);
+    io_thread->set_pollin (handle);
 
     //  Initialise the termination and check whether it can be deallocated
     //  immediately.
@@ -843,8 +843,8 @@ void xs::socket_base_t::check_destroy ()
     //  If the object was already marked as destroyed, finish the deallocation.
     if (destroyed) {
 
-        //  Remove the socket from the reaper's poller.
-        poller->rm_fd (handle);
+        //  Remove the socket from the reaper's I/O thread.
+        io_thread->rm_fd (handle);
 
         //  Remove the socket from the context.
         destroy_socket (this);
diff --git a/src/socket_base.hpp b/src/socket_base.hpp
index 8b9a948..dd1fee7 100644
--- a/src/socket_base.hpp
+++ b/src/socket_base.hpp
@@ -28,7 +28,7 @@
 #include "own.hpp"
 #include "array.hpp"
 #include "stdint.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 #include "atomic_counter.hpp"
 #include "mailbox.hpp"
 #include "stdint.hpp"
@@ -83,12 +83,12 @@ namespace xs
         bool has_in ();
         bool has_out ();
 
-        //  Using this function reaper thread ask the socket to regiter with
-        //  its poller.
-        void start_reaping (poller_base_t *poller_);
+        //  Using this function reaper thread asks the socket to regiter with
+        //  its I/O thread.
+        void start_reaping (io_thread_t *io_thread_);
 
         //  i_poll_events implementation. This interface is used when socket
-        //  is handled by the poller in the reaper thread.
+        //  is handled by the io_thread in the reaper thread.
         void in_event (fd_t fd_);
         void out_event (fd_t fd_);
         void timer_event (handle_t handle_);
@@ -188,8 +188,8 @@ namespace xs
         typedef array_t <pipe_t, 3> pipes_t;
         pipes_t pipes;
 
-        //  Reaper's poller and handle of this socket within it.
-        poller_base_t *poller;
+        //  Reaper's io_thread and handle of this socket within it.
+        io_thread_t *io_thread;
         handle_t handle;
 
         //  Timestamp of when commands were processed the last time.
diff --git a/src/stream_engine.cpp b/src/stream_engine.cpp
index 7d69848..71032f4 100644
--- a/src/stream_engine.cpp
+++ b/src/stream_engine.cpp
@@ -36,7 +36,7 @@
 #include <new>
 
 #include "stream_engine.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 #include "session_base.hpp"
 #include "config.hpp"
 #include "err.hpp"
@@ -103,7 +103,7 @@ xs::stream_engine_t::~stream_engine_t ()
     }
 }
 
-void xs::stream_engine_t::plug (poller_base_t *io_thread_,
+void xs::stream_engine_t::plug (io_thread_t *io_thread_,
     session_base_t *session_)
 {
     xs_assert (!plugged);
@@ -117,7 +117,7 @@ void xs::stream_engine_t::plug (poller_base_t *io_thread_,
     decoder.set_session (session_);
     session = session_;
 
-    //  Connect to I/O threads poller object.
+    //  Connect to the io_thread object.
     io_object_t::plug (io_thread_);
     handle = add_fd (s);
     set_pollin (handle);
@@ -135,7 +135,7 @@ void xs::stream_engine_t::unplug ()
     //  Cancel all fd subscriptions.
     rm_fd (handle);
 
-    //  Disconnect from I/O threads poller object.
+    //  Disconnect from the io_thread object.
     io_object_t::unplug ();
 
     //  Disconnect from session object.
diff --git a/src/stream_engine.hpp b/src/stream_engine.hpp
index 9060cd7..f246552 100644
--- a/src/stream_engine.hpp
+++ b/src/stream_engine.hpp
@@ -34,7 +34,7 @@
 namespace xs
 {
 
-    class poller_base_t;
+    class io_thread_t;
     class session_base_t;
 
     //  This engine handles any socket with SOCK_STREAM semantics,
@@ -48,7 +48,7 @@ namespace xs
         ~stream_engine_t ();
 
         //  i_engine interface implementation.
-        void plug (xs::poller_base_t *io_thread_,
+        void plug (xs::io_thread_t *io_thread_,
            xs::session_base_t *session_);
         void unplug ();
         void terminate ();
diff --git a/src/sub.cpp b/src/sub.cpp
index 08ce368..ad55ea3 100644
--- a/src/sub.cpp
+++ b/src/sub.cpp
@@ -80,7 +80,7 @@ bool xs::sub_t::xhas_out ()
     return false;
 }
 
-xs::sub_session_t::sub_session_t (poller_base_t *io_thread_, bool connect_,
+xs::sub_session_t::sub_session_t (io_thread_t *io_thread_, bool connect_,
       socket_base_t *socket_, const options_t &options_,
       const char *protocol_, const char *address_) :
     xsub_session_t (io_thread_, connect_, socket_, options_, protocol_,
diff --git a/src/sub.hpp b/src/sub.hpp
index 9b38822..70ade88 100644
--- a/src/sub.hpp
+++ b/src/sub.hpp
@@ -29,7 +29,7 @@ namespace xs
 
     class ctx_t;
     class msg_t;
-    class poller_base_t;
+    class io_thread_t;
     class socket_base_t;
 
     class sub_t : public xsub_t
@@ -55,7 +55,7 @@ namespace xs
     {
     public:
 
-        sub_session_t (xs::poller_base_t *io_thread_, bool connect_,
+        sub_session_t (xs::io_thread_t *io_thread_, bool connect_,
             xs::socket_base_t *socket_, const options_t &options_,
             const char *protocol_, const char *address_);
         ~sub_session_t ();
diff --git a/src/tcp_connecter.cpp b/src/tcp_connecter.cpp
index 6816e64..5007570 100644
--- a/src/tcp_connecter.cpp
+++ b/src/tcp_connecter.cpp
@@ -24,7 +24,7 @@
 
 #include "tcp_connecter.hpp"
 #include "stream_engine.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 #include "platform.hpp"
 #include "random.hpp"
 #include "err.hpp"
@@ -46,7 +46,7 @@
 #endif
 #endif
 
-xs::tcp_connecter_t::tcp_connecter_t (class poller_base_t *io_thread_,
+xs::tcp_connecter_t::tcp_connecter_t (class io_thread_t *io_thread_,
       class session_base_t *session_, const options_t &options_,
       const char *address_, bool wait_) :
     own_t (io_thread_, options_),
diff --git a/src/tcp_connecter.hpp b/src/tcp_connecter.hpp
index 2b946a1..6790408 100644
--- a/src/tcp_connecter.hpp
+++ b/src/tcp_connecter.hpp
@@ -31,7 +31,7 @@
 namespace xs
 {
 
-    class poller_base_t;
+    class io_thread_t;
     class session_base_t;
 
     class tcp_connecter_t : public own_t, public io_object_t
@@ -40,7 +40,7 @@ namespace xs
 
         //  If 'delay' is true connecter first waits for a while, then starts
         //  connection process.
-        tcp_connecter_t (xs::poller_base_t *io_thread_,
+        tcp_connecter_t (xs::io_thread_t *io_thread_,
             xs::session_base_t *session_, const options_t &options_,
             const char *address_, bool delay_);
         ~tcp_connecter_t ();
@@ -91,7 +91,7 @@ namespace xs
         fd_t s;
 
         //  Handle corresponding to the listening socket or NULL if the socket
-        //  is not registered with the poller.
+        //  is not registered with the I/O thread.
         handle_t handle;
 
         //  If true, connecter is waiting a while before trying to connect.
diff --git a/src/tcp_listener.cpp b/src/tcp_listener.cpp
index e8900fc..31a9149 100644
--- a/src/tcp_listener.cpp
+++ b/src/tcp_listener.cpp
@@ -26,7 +26,7 @@
 #include "platform.hpp"
 #include "tcp_listener.hpp"
 #include "stream_engine.hpp"
-#include "poller_base.hpp"
+#include "io_thread.hpp"
 #include "session_base.hpp"
 #include "config.hpp"
 #include "err.hpp"
@@ -48,7 +48,7 @@
 #include <ioctl.h>
 #endif
 
-xs::tcp_listener_t::tcp_listener_t (poller_base_t *io_thread_,
+xs::tcp_listener_t::tcp_listener_t (io_thread_t *io_thread_,
       socket_base_t *socket_, const options_t &options_) :
     own_t (io_thread_, options_),
     io_object_t (io_thread_),
@@ -94,7 +94,7 @@ void xs::tcp_listener_t::in_event (fd_t fd_)
 
     //  Choose I/O thread to run connecter in. Given that we are already
     //  running in an I/O thread, there must be at least one available.
-    poller_base_t *io_thread = choose_io_thread (options.affinity);
+    io_thread_t *io_thread = choose_io_thread (options.affinity);
     xs_assert (io_thread);
 
     //  Create and launch a session object. 
diff --git a/src/tcp_listener.hpp b/src/tcp_listener.hpp
index 22c000f..153f771 100644
--- a/src/tcp_listener.hpp
+++ b/src/tcp_listener.hpp
@@ -31,14 +31,14 @@
 namespace xs
 {
 
-    class poller_base_t;
+    class io_thread_t;
     class socket_base_t;
 
     class tcp_listener_t : public own_t, public io_object_t
     {
     public:
 
-        tcp_listener_t (xs::poller_base_t *io_thread_,
+        tcp_listener_t (xs::io_thread_t *io_thread_,
             xs::socket_base_t *socket_, const options_t &options_);
         ~tcp_listener_t ();
 
diff --git a/src/xpub.cpp b/src/xpub.cpp
index 6c0f75b..d27337e 100644
--- a/src/xpub.cpp
+++ b/src/xpub.cpp
@@ -182,7 +182,7 @@ void xs::xpub_t::send_unsubscription (unsigned char *data_, size_t size_,
     }
 }
 
-xs::xpub_session_t::xpub_session_t (poller_base_t *io_thread_, bool connect_,
+xs::xpub_session_t::xpub_session_t (io_thread_t *io_thread_, bool connect_,
       socket_base_t *socket_, const options_t &options_,
       const char *protocol_, const char *address_) :
     session_base_t (io_thread_, connect_, socket_, options_, protocol_,
diff --git a/src/xpub.hpp b/src/xpub.hpp
index 2c61c63..a26076e 100644
--- a/src/xpub.hpp
+++ b/src/xpub.hpp
@@ -37,7 +37,7 @@ namespace xs
     class ctx_t;
     class msg_t;
     class pipe_t;
-    class poller_base_t;
+    class io_thread_t;
 
     class xpub_t :
         public socket_base_t
@@ -89,7 +89,7 @@ namespace xs
     {
     public:
 
-        xpub_session_t (xs::poller_base_t *io_thread_, bool connect_,
+        xpub_session_t (xs::io_thread_t *io_thread_, bool connect_,
             socket_base_t *socket_, const options_t &options_,
             const char *protocol_, const char *address_);
         ~xpub_session_t ();
diff --git a/src/xrep.cpp b/src/xrep.cpp
index 4bae2d9..051159d 100644
--- a/src/xrep.cpp
+++ b/src/xrep.cpp
@@ -307,7 +307,7 @@ bool xs::xrep_t::xhas_out ()
     return true;
 }
 
-xs::xrep_session_t::xrep_session_t (poller_base_t *io_thread_, bool connect_,
+xs::xrep_session_t::xrep_session_t (io_thread_t *io_thread_, bool connect_,
       socket_base_t *socket_, const options_t &options_,
       const char *protocol_, const char *address_) :
     session_base_t (io_thread_, connect_, socket_, options_, protocol_,
diff --git a/src/xrep.hpp b/src/xrep.hpp
index e5ab895..4b3192a 100644
--- a/src/xrep.hpp
+++ b/src/xrep.hpp
@@ -37,7 +37,7 @@ namespace xs
 
     class ctx_t;
     class pipe_t;
-    class poller_base_t;
+    class io_thread_t;
 
     //  TODO: This class uses O(n) scheduling. Rewrite it to use O(1) algorithm.
     class xrep_t :
@@ -109,7 +109,7 @@ namespace xs
     {
     public:
 
-        xrep_session_t (xs::poller_base_t *io_thread_, bool connect_,
+        xrep_session_t (xs::io_thread_t *io_thread_, bool connect_,
             socket_base_t *socket_, const options_t &options_,
             const char *protocol_, const char *address_);
         ~xrep_session_t ();
diff --git a/src/xreq.cpp b/src/xreq.cpp
index 948ff22..d16f60e 100644
--- a/src/xreq.cpp
+++ b/src/xreq.cpp
@@ -115,7 +115,7 @@ void xs::xreq_t::xterminated (pipe_t *pipe_)
     lb.terminated (pipe_);
 }
 
-xs::xreq_session_t::xreq_session_t (poller_base_t *io_thread_, bool connect_,
+xs::xreq_session_t::xreq_session_t (io_thread_t *io_thread_, bool connect_,
       socket_base_t *socket_, const options_t &options_,
       const char *protocol_, const char *address_) :
     session_base_t (io_thread_, connect_, socket_, options_, protocol_,
diff --git a/src/xreq.hpp b/src/xreq.hpp
index 358b10a..ab3a360 100644
--- a/src/xreq.hpp
+++ b/src/xreq.hpp
@@ -32,7 +32,7 @@ namespace xs
     class ctx_t;
     class msg_t;
     class pipe_t;
-    class poller_base_t;
+    class io_thread_t;
     class socket_base_t;
 
     class xreq_t :
@@ -76,7 +76,7 @@ namespace xs
     {
     public:
 
-        xreq_session_t (xs::poller_base_t *io_thread_, bool connect_,
+        xreq_session_t (xs::io_thread_t *io_thread_, bool connect_,
             xs::socket_base_t *socket_, const options_t &options_,
             const char *protocol_, const char *address_);
         ~xreq_session_t ();
diff --git a/src/xsub.cpp b/src/xsub.cpp
index ee53b2c..80cc205 100644
--- a/src/xsub.cpp
+++ b/src/xsub.cpp
@@ -221,7 +221,7 @@ void xs::xsub_t::send_subscription (unsigned char *data_, size_t size_,
     xs_assert (sent);
 }
 
-xs::xsub_session_t::xsub_session_t (poller_base_t *io_thread_, bool connect_,
+xs::xsub_session_t::xsub_session_t (io_thread_t *io_thread_, bool connect_,
       socket_base_t *socket_, const options_t &options_,
       const char *protocol_, const char *address_) :
     session_base_t (io_thread_, connect_, socket_, options_, protocol_,
diff --git a/src/xsub.hpp b/src/xsub.hpp
index 8769706..f9e5210 100644
--- a/src/xsub.hpp
+++ b/src/xsub.hpp
@@ -32,7 +32,7 @@ namespace xs
 
     class ctx_t;
     class pipe_t;
-    class poller_base_t;
+    class io_thread_t;
 
     class xsub_t :
         public socket_base_t
@@ -91,7 +91,7 @@ namespace xs
     {
     public:
 
-        xsub_session_t (class poller_base_t *io_thread_, bool connect_,
+        xsub_session_t (class io_thread_t *io_thread_, bool connect_,
             socket_base_t *socket_, const options_t &options_,
             const char *protocol_, const char *address_);
         ~xsub_session_t ();