Changeset 7160

Timestamp:

Nov 26, 2008, 6:00:37 PM (12 years ago)

Author:

charles

Message:

(libT) make the the speed measurements a little more accurate

File:

• trunk/libtransmission/bandwidth.c (modified) (6 diffs)

trunk/libtransmission/bandwidth.c

@@ -30 +30 @@
     HISTORY_MSEC = 2000,
     INTERVAL_MSEC = HISTORY_MSEC,
-    GRANULARITY_MSEC = 250,
+    GRANULARITY_MSEC = 40,
     HISTORY_SIZE = ( INTERVAL_MSEC / GRANULARITY_MSEC ),
     MAGIC_NUMBER = 43143
@@ -42 +42 @@
 
 static float
-getSpeed( const struct bratecontrol * r )
-{
-    const uint64_t interval_msec = HISTORY_MSEC;
+getSpeed( const struct bratecontrol * r, int interval_msec )
+{
     uint64_t       bytes = 0;
     const uint64_t cutoff = tr_date ( ) - interval_msec;
@@ -241 +240 @@
 }
 
-#if 0
+#if 1
 #define DEBUG_DIRECTION TR_UP
 #endif
@@ -259 +258 @@
         const double currentSpeed = tr_bandwidthGetPieceSpeed( b, dir ); /* KiB/s */
         const double desiredSpeed = b->band[dir].desiredSpeed;           /* KiB/s */
-        const double seconds_per_pulse = period_msec / 1000.0;
-        const double current_bytes_per_pulse = currentSpeed * 1024.0 * seconds_per_pulse;
-        const double desired_bytes_per_pulse = desiredSpeed * 1024.0 * seconds_per_pulse;
-        const double pulses_per_history = (double)HISTORY_MSEC / period_msec;
-        const double min = desired_bytes_per_pulse * 0.85;
-        const double max = desired_bytes_per_pulse * 1.15;
-        const double next_pulse_bytes = desired_bytes_per_pulse * ( pulses_per_history + 1 )
-                                      - ( current_bytes_per_pulse * pulses_per_history );
-
-        /* clamp the return value to lessen oscillation */
-        clamped = next_pulse_bytes;
-        clamped = MAX( clamped, min );
-        clamped = MIN( clamped, max );
-
-        b->band[dir].bytesLeft = clamped;
+        const double pulseCount = HISTORY_MSEC / (double)period_msec;
+        const double nextPulseSpeed = desiredSpeed * ( pulseCount + 1 ) - ( currentSpeed * pulseCount );
+        b->band[dir].bytesLeft = nextPulseSpeed * 1024.0 * period_msec / 1000.0;
 
 #ifdef DEBUG_DIRECTION
         if( dir == DEBUG_DIRECTION )
-                fprintf( stderr, "bandwidth %p currentPieceSpeed(%5.2f of %5.2f) desiredSpeed(%5.2f), allocating %5.2f (unclamped: %5.2f)\n",
+                fprintf( stderr, "bandwidth %p currentPieceSpeed(%5.2f of %5.2f) desiredSpeed(%5.2f), allocating %5.2f\n",
                          b, currentSpeed, tr_bandwidthGetRawSpeed( b, dir ), desiredSpeed,
-                         clamped/1024.0, next_pulse_bytes/1024.0 );
+                         b->band[dir].bytesLeft/1024.0 );
 #endif
     }
 
     /* notify the io buffers that there's more bandwidth available */
-    if( !b->band[dir].isLimited || ( clamped > 0.001 ) )
+    if( !b->band[dir].isLimited || ( b->band[dir].bytesLeft > 0 ) )
     {
         int i, n=0;
@@ -360 +347 @@
     assert( isDirection( dir ) );
 
-    return getSpeed( &b->band[dir].raw );
+    return getSpeed( &b->band[dir].raw, HISTORY_MSEC );
 }
 
@@ -369 +356 @@
     assert( isDirection( dir ) );
 
-    return getSpeed( &b->band[dir].piece );
+    return getSpeed( &b->band[dir].piece, HISTORY_MSEC );
 }