Use time.perf_counter instead of time.monotonic (#114)

Use time.perf_counter instead of time.monotonic. Fixes 113

Author: pylessard

doc/source/index.rst

@@ -47,4 +47,5 @@ On top of that, some improvement makes v2.x preferable over v1.x
     - Sending data with a generator is now possible, accommodating use cases with large payloads
     - The module is fully type-hinted
     - It is possible to use a busy-wait to achieve even more precise timings. See the :ref:`wait_func parameter<param_wait_func>`
+    - Performances on Windows are greatly improved by the usage of ``time.perf_counter`` instead of ``time.monotonic``. See `issue #113 <https://github.com/pylessard/python-can-isotp/issues/113>`_
 

isotp/protocol.py

@@ -259,7 +259,7 @@ def update(self) -> None:
             self.reset()
             return
 
-        t = time.monotonic()
+        t = time.perf_counter()
 
         while len(self.burst_time) > 0:
             t2 = self.burst_time[0]
@@ -283,7 +283,7 @@ def allowed_bytes(self) -> int:
     def inform_byte_sent(self, datalen: int) -> None:
         if self.enabled:
             bytelen = datalen * 8
-            t = time.monotonic()
+            t = time.perf_counter()
             self.bit_total += bytelen
             if len(self.burst_time) == 0:
                 self.burst_time.append(t)
@@ -689,7 +689,7 @@ def load_params(self) -> None:
     def send(self,
              data: Union[bytes, bytearray, SendGenerator],
              target_address_type: Optional[Union[isotp.address.TargetAddressType, int]] = None,
-             send_timeout: float = 0):
+             send_timeout: Optional[float] = None):
         """
         Enqueue an IsoTP frame to be sent over CAN network.
         When performing a blocking send, this method returns only when the transmission is complete or raise an exception when a failure or a timeout occurs.
@@ -704,7 +704,7 @@ def send(self,
         :type target_address_type: int
 
         :param send_timeout: Timeout value for blocking send. Unused if :ref:`blocking_send<param_blocking_send>` is ``False``
-        :type send_timeout: float
+        :type send_timeout: float or None
 
         :raises ValueError: Given data is not a bytearray, a tuple (generator,size) or the size is too big
         :raises RuntimeError: Transmit queue is full
@@ -1583,9 +1583,9 @@ def _relay_thread_fn(self) -> None:
         self.events.relay_thread_ready.set()
         while not self.events.stop_requested.is_set():
             rx_timeout = 0.0 if self.is_tx_throttled() else self.default_read_timeout
-            t1 = time.monotonic()
+            t1 = time.perf_counter()
             data = self.user_rxfn(rx_timeout)
-            diff = time.monotonic() - t1
+            diff = time.perf_counter() - t1
             if data is not None:
                 self.rx_relay_queue.put(data)
             else:   # No data received. Sleep if user is not blocking

isotp/tools.py

@@ -20,20 +20,20 @@ def set_timeout(self, timeout: float) -> None:
     def start(self, timeout=None) -> None:
         if timeout is not None:
             self.set_timeout(timeout)
-        self.start_time = time.monotonic_ns()
+        self.start_time = time.perf_counter_ns()
 
     def stop(self) -> None:
         self.start_time = None
 
     def elapsed(self) -> float:
         if self.start_time is not None:
-            return float(time.monotonic_ns() - self.start_time) / 1.0e9
+            return float(time.perf_counter_ns() - self.start_time) / 1.0e9
         else:
             return 0
 
     def elapsed_ns(self) -> int:
         if self.start_time is not None:
-            return time.monotonic_ns() - self.start_time
+            return time.perf_counter_ns() - self.start_time
         else:
             return 0