Changes to determining can_be_slowed (#1891)

* Changes to determining can_be_slowed

* Add return type for get_stable_speed and make can_be_slowed local

sabnzbd/bpsmeter.py

@@ -425,14 +425,22 @@ class BPSMeter:
         # We record every second, but display at the user's refresh-rate
         return self.bps_list[::refresh_rate]
 
-    def get_stable_speed(self, timespan=10):
+    def get_stable_speed(self, timespan: int = 10) -> Optional[int]:
         """See if there is a stable speed the last <timespan> seconds
         None: indicates it can't determine yet
-        False: the speed was not stable during <timespan>
+        0: the speed was not stable during <timespan>
+        Positive float: the speed was stable
         """
         if len(self.bps_list) < timespan:
             return None
 
+        # Check if speed fell by more than 15%
+        try:
+            if self.bps_list[-1] / self.bps_list[-timespan] < 0.85:
+                return 0
+        except:
+            pass
+
         # Calculate the variance in the speed
         avg = sum(self.bps_list[-timespan:]) / timespan
         vari = 0
@@ -445,7 +453,7 @@ class BPSMeter:
             if (vari / (self.bps / KIBI)) < 0.05:
                 return avg
             else:
-                return False
+                return 0
         except:
             # Probably one of the values was 0
             pass

sabnzbd/downloader.py

@@ -242,8 +242,6 @@ class Downloader(Thread):
         "paused",
         "bandwidth_limit",
         "bandwidth_perc",
-        "can_be_slowed",
-        "can_be_slowed_timer",
         "sleep_time",
         "paused_for_postproc",
         "shutdown",
@@ -270,8 +268,6 @@ class Downloader(Thread):
         self.speed_set()
 
         # Used to see if we can add a slowdown to the Downloader-loop
-        self.can_be_slowed: Optional[bool] = None
-        self.can_be_slowed_timer: int = 0
         self.sleep_time: float = 0.0
         self.sleep_time_set()
         cfg.downloader_sleep_time.callback(self.sleep_time_set)
@@ -544,6 +540,11 @@ class Downloader(Thread):
         BPSMeter.update()
         next_bpsmeter_update = 0
 
+        # can_be_slowed variables
+        can_be_slowed: Optional[float] = None
+        can_be_slowed_timer: float = 0.0
+        next_stable_speed_check: float = 0.0
+
         # Check server expiration dates
         check_server_expiration()
 
@@ -678,21 +679,29 @@ class Downloader(Thread):
                 read, _, _ = select.select(readkeys, (), (), 1.0)
 
                 # Add a sleep if there are too few results compared to the number of active connections
-                if self.can_be_slowed and len(read) < 1 + len(readkeys) / 10:
-                    time.sleep(self.sleep_time)
-
-                # Need to initialize the check during first 20 seconds
-                if self.can_be_slowed is None or self.can_be_slowed_timer:
-                    # Wait for stable speed to start testing
-                    if not self.can_be_slowed_timer and BPSMeter.get_stable_speed(timespan=10):
-                        self.can_be_slowed_timer = time.time()
-
-                    # Check 10 seconds after enabling slowdown
-                    if self.can_be_slowed_timer and time.time() > self.can_be_slowed_timer + 10:
-                        # Now let's check if it was stable in the last 10 seconds
-                        self.can_be_slowed = BPSMeter.get_stable_speed(timespan=10)
-                        self.can_be_slowed_timer = 0
-                        logging.debug("Downloader-slowdown: %r", self.can_be_slowed)
+                if self.sleep_time:
+                    if can_be_slowed and len(read) < 1 + len(readkeys) / 10:
+                        time.sleep(self.sleep_time)
+
+                    # Initialize by waiting for stable speed and then enable sleep
+                    if can_be_slowed is None or can_be_slowed_timer:
+                        # Wait for stable speed to start testing
+
+                        if not can_be_slowed_timer and now > next_stable_speed_check:
+                            if BPSMeter.get_stable_speed(timespan=10):
+                                can_be_slowed_timer = now + 8
+                                can_be_slowed = 1
+                            else:
+                                next_stable_speed_check = now + _BPSMETER_UPDATE_DELAY
+
+                        # Check 10 seconds after enabling slowdown
+                        if can_be_slowed_timer and now > can_be_slowed_timer:
+                            # Now let's check if it was stable in the last 10 seconds
+                            can_be_slowed = BPSMeter.get_stable_speed(timespan=10)
+                            can_be_slowed_timer = 0
+                            if not can_be_slowed:
+                                self.sleep_time = 0
+                            logging.debug("Downloader-slowdown: %r", can_be_slowed)
 
             else:
                 read = []