use better high precision timer for Linux

src/server.cpp

@@ -26,67 +26,7 @@
 
 
 // CHighPrecisionTimer implementation ******************************************
-#if defined ( __APPLE__ ) || defined ( __MACOSX )
-#include <mach/mach.h>
-#include <mach/mach_error.h>
-#include <mach/mach_time.h>
-
-CHighPrecisionTimer::CHighPrecisionTimer() :
-    bRun ( false )
-{
-    // calculate delay in mach absolute time
-    const uint64_t iNsDelay =
-        ( (uint64_t) SYSTEM_FRAME_SIZE_SAMPLES * 1000000000 ) /
-        (uint64_t) SYSTEM_SAMPLE_RATE_HZ; // in ns
-
-    struct mach_timebase_info timeBaseInfo;
-    mach_timebase_info ( &timeBaseInfo );
-
-    iMachDelay = ( iNsDelay * (uint64_t) timeBaseInfo.denom ) /
-        (uint64_t) timeBaseInfo.numer;
-}
-
-void CHighPrecisionTimer::Start()
-{
-    // only start if not already running
-    if ( !bRun )
-    {
-        // set run flag
-        bRun = true;
-
-        // set initial end time
-        iNextEnd = mach_absolute_time() + iMachDelay;
-
-        // start thread
-        QThread::start();
-    }
-}
-
-void CHighPrecisionTimer::Stop()
-{
-    // set flag so that thread can leave the main loop
-    bRun = false;
-
-    // give thread some time to terminate
-    wait ( 5000 );
-}
-
-void CHighPrecisionTimer::run()
-{
-    // loop until the thread shall be terminated
-    while ( bRun )
-    {
-        // call processing routine by fireing signal
-        emit timeout();
-
-        // now wait until the next buffer shall be processed (we
-        // use the "increment method" to make sure we do not introduce
-        // a timing drift)
-        mach_wait_until(iNextEnd);
-        iNextEnd += iMachDelay;
-    }
-}
-#else
+#ifdef _WIN32
 CHighPrecisionTimer::CHighPrecisionTimer()
 {
     // add some error checking, the high precision timer implementation only
@@ -94,7 +34,7 @@ CHighPrecisionTimer::CHighPrecisionTimer()
 #if ( SYSTEM_FRAME_SIZE_SAMPLES != 128 )
 # error "Only system frame size of 128 samples is supported by this module"
 #endif
-#if SYSTEM_SAMPLE_RATE_HZ != 48000
+#if ( SYSTEM_SAMPLE_RATE_HZ != 48000 )
 # error "Only a system sample rate of 48 kHz is supported by this module"
 #endif
 
@@ -160,6 +100,82 @@ void CHighPrecisionTimer::OnTimer()
         iIntervalCounter++;
     }
 }
+#else // Mac and Linux
+CHighPrecisionTimer::CHighPrecisionTimer() :
+    bRun ( false )
+{
+    // calculate delay in ns
+    const uint64_t iNsDelay =
+        ( (uint64_t) SYSTEM_FRAME_SIZE_SAMPLES * 1000000000 ) /
+        (uint64_t) SYSTEM_SAMPLE_RATE_HZ; // in ns
+
+#if defined ( __APPLE__ ) || defined ( __MACOSX )
+    // calculate delay in mach absolute time
+    struct mach_timebase_info timeBaseInfo;
+    mach_timebase_info ( &timeBaseInfo );
+
+    Delay = ( iNsDelay * (uint64_t) timeBaseInfo.denom ) /
+        (uint64_t) timeBaseInfo.numer;
+#else
+    // set delay
+    Delay.tv_sec  = 0;
+    Delay.tv_nsec = iNsDelay;
+#endif
+}
+
+void CHighPrecisionTimer::Start()
+{
+    // only start if not already running
+    if ( !bRun )
+    {
+        // set run flag
+        bRun = true;
+
+        // set initial end time
+#if defined ( __APPLE__ ) || defined ( __MACOSX )
+        NextEnd = mach_absolute_time();
+#else
+        clock_gettime ( CLOCK_MONOTONIC, NextEnd );
+#endif
+        NextEnd += Delay;
+
+        // start thread
+        QThread::start();
+    }
+}
+
+void CHighPrecisionTimer::Stop()
+{
+    // set flag so that thread can leave the main loop
+    bRun = false;
+
+    // give thread some time to terminate
+    wait ( 5000 );
+}
+
+void CHighPrecisionTimer::run()
+{
+    // loop until the thread shall be terminated
+    while ( bRun )
+    {
+        // call processing routine by fireing signal
+        emit timeout();
+
+        // now wait until the next buffer shall be processed (we
+        // use the "increment method" to make sure we do not introduce
+        // a timing drift)
+#if defined ( __APPLE__ ) || defined ( __MACOSX )
+        mach_wait_until ( NextEnd );
+#else
+        clock_nanosleep ( CLOCK_MONOTONIC,
+                          TIMER_ABSTIME,
+                          NextEnd,
+                          NULL );
+#endif
+
+        NextEnd += Delay;
+    }
+}
 #endif
 
 

src/server.h

@@ -43,36 +43,10 @@
 // no valid channel number
 #define INVALID_CHANNEL_ID                  ( MAX_NUM_CHANNELS + 1 )
 
-// minimum timer precision
-#define MIN_TIMER_RESOLUTION_MS             1 // ms
-
 
 /* Classes ********************************************************************/
-#if defined ( __APPLE__ ) || defined ( __MACOSX )
-// using mach timers for Mac
-class CHighPrecisionTimer : public QThread
-{
-    Q_OBJECT
-
-public:
-    CHighPrecisionTimer();
-
-    void Start();
-    void Stop();
-    bool isActive() { return bRun; }
-
-protected:
-    virtual void run();
-
-    bool     bRun;
-    uint64_t iMachDelay;
-    uint64_t iNextEnd;
-
-signals:
-    void timeout();
-};
-#else
-// using QTimer for Windows and Linux
+#if ( defined ( WIN32 ) || defined ( _WIN32 ) )
+// using QTimer for Windows
 class CHighPrecisionTimer : public QObject
 {
     Q_OBJECT
@@ -93,6 +67,43 @@ protected:
 public slots:
     void OnTimer();
 
+signals:
+    void timeout();
+};
+#else
+// using mach timers for Mac and nanosleep for Linux
+#if defined ( __APPLE__ ) || defined ( __MACOSX )
+# include <mach/mach.h>
+# include <mach/mach_error.h>
+# include <mach/mach_time.h>
+#else
+# include <sys/time.h>
+#endif
+
+class CHighPrecisionTimer : public QThread
+{
+    Q_OBJECT
+
+public:
+    CHighPrecisionTimer();
+
+    void Start();
+    void Stop();
+    bool isActive() { return bRun; }
+
+protected:
+    virtual void run();
+
+    bool bRun;
+
+#if defined ( __APPLE__ ) || defined ( __MACOSX )
+    uint64_t Delay;
+    uint64_t NextEnd;
+#else
+    timespec Delay;
+    timespec NextEnd;
+#endif
+
 signals:
     void timeout();
 };