Scheduler: Implement timer source switching API

[senf.git] / Scheduler / Scheduler.hh

diff --git a/Scheduler/Scheduler.hh b/Scheduler/Scheduler.hh
index af07c48..fdd5f59 100644 (file)
--- a/Scheduler/Scheduler.hh
+++ b/Scheduler/Scheduler.hh
@@ -24,14 +24,15 @@
     \brief Scheduler public header
  */
 
-#ifndef HH_Scheduler_
-#define HH_Scheduler_ 1
+#ifndef HH_SENF_Scheduler_Scheduler_
+#define HH_SENF_Scheduler_Scheduler_ 1
 
 // Custom includes
 #include "../Utils/Logger/SenfLog.hh"
 #include "FdEvent.hh"
 #include "TimerEvent.hh"
 #include "SignalEvent.hh"
+#include "EventHook.hh"
 
 //#include "scheduler.mpp"
 ///////////////////////////////hh.p////////////////////////////////////////
@@ -64,6 +65,7 @@ namespace senf {
     \li senf::scheduler::FdEvent for file descriptor events
     \li senf::scheduler::TimerEvent for single-shot deadline timer events
     \li senf::scheduler::SignalEvent for UNIX signal events
+    \li senf::scheduler::EventHook for a special event hook
 
     These instance are owned and managed by the user of the scheduler \e not by the scheduler so the
     RAII concept can be used.
@@ -230,6 +232,32 @@ namespace scheduler {
     /** \brief Number of watchdog events */
     unsigned hangCount(); 
 
+    /** \brief Switch to using hi resolution timers
+        
+        By default, timers are implemented directly using epoll. This however restricts the timer
+        resolution to that of the kernel HZ value.
+
+        High resolution timers are implemented either using POSIX timers or, when available, using
+        the Linux special \c timerfd() syscall.
+
+        POSIX timers are delivered using signals. A high timer load this increases the signal load
+        considerably. \c timerfd()'s are delivered on a file descriptor and thus don't have such a
+        scalability issue.
+
+        \warning The timer source must not be switched from a scheduler callback
+     */
+    void hiresTimers();
+
+    /** \brief Switch back to using epoll for timing
+        \see hiresTimers()
+     */
+    void loresTimers();
+
+    /** \brief return \c true, if \c timerfd() timing is available, \c false otherwise
+        \see hiresTimers()
+     */
+    bool haveScalableHiresTimers();
+
     /** \brief Restart scheduler
         
         This call will restart all scheduler dispatchers (timers, signals, file descriptors). This