feat(cli): support float number as snapshot interval (>= 0.25s)

nvitop/cli.py

@@ -31,13 +31,13 @@ def parse_arguments() -> argparse.Namespace:
         colored('heavy', 'red'),
     )
 
-    def posint(argstring: str) -> int:
-        num = int(argstring)
+    def posfloat(argstring: str) -> float:
+        num = float(argstring)
         if num <= 0:
             raise ValueError
         return num
 
-    posint.__name__ = 'positive integer'
+    posfloat.__name__ = 'positive float'
 
     parser = argparse.ArgumentParser(
         prog='nvitop',
@@ -88,7 +88,7 @@ def parse_arguments() -> argparse.Namespace:
     parser.add_argument(
         '--interval',
         dest='interval',
-        type=posint,
+        type=posfloat,
         default=None,
         metavar='SEC',
         help='Process status update interval in seconds. (default: 2)',
@@ -223,6 +223,12 @@ def parse_arguments() -> argparse.Namespace:
 
     args = parser.parse_args()
 
+    if args.interval is not None and args.interval < 0.25:
+        parser.error(
+            f'the interval {args.interval:0.2g}s is too short, which may cause performance issues. '
+            f'Expected 1/4 or higher.',
+        )
+
     if not args.colorful:
         args.colorful = 'colorful' in NVITOP_MONITOR_MODE and 'plain' not in NVITOP_MONITOR_MODE
     if not args.light:

nvitop/gui/screens/main/device.py

@@ -14,7 +14,7 @@ from nvitop.version import __version__
 
 class DevicePanel(Displayable):  # pylint: disable=too-many-instance-attributes
     NAME = 'device'
-    SNAPSHOT_INTERVAL = 0.67
+    SNAPSHOT_INTERVAL = 0.5
 
     def __init__(self, devices, compact, win, root):
         super().__init__(win, root)
@@ -127,6 +127,16 @@ class DevicePanel(Displayable):  # pylint: disable=too-many-instance-attributes
         with self.snapshot_lock:
             self._snapshots = snapshots
 
+    @classmethod
+    def set_snapshot_interval(cls, interval):
+        assert interval > 0.0
+        interval = float(interval)
+
+        cls.SNAPSHOT_INTERVAL = min(interval / 3.0, 1.0)
+        cls.take_snapshots = ttl_cache(ttl=interval)(
+            cls.take_snapshots.__wrapped__,  # pylint: disable=no-member
+        )
+
     @ttl_cache(ttl=1.0)
     def take_snapshots(self):
         snapshots = [device.as_snapshot() for device in self.all_devices]

nvitop/gui/screens/main/host.py

@@ -165,6 +165,13 @@ class HostPanel(Displayable):  # pylint: disable=too-many-instance-attributes
             format=lambda x: f'{prefix}GPU UTL: {percentage(x)}',
         )
 
+    @classmethod
+    def set_snapshot_interval(cls, interval):
+        assert interval > 0.0
+        interval = float(interval)
+
+        cls.SNAPSHOT_INTERVAL = min(interval / 3.0, 0.5)
+
     def take_snapshots(self):
         host.cpu_percent()
         host.virtual_memory()

nvitop/gui/screens/main/process.py

@@ -34,7 +34,7 @@ Order = namedtuple('Order', ['key', 'reverse', 'offset', 'column', 'previous', '
 
 class ProcessPanel(Displayable):  # pylint: disable=too-many-instance-attributes
     NAME = 'process'
-    SNAPSHOT_INTERVAL = 0.67
+    SNAPSHOT_INTERVAL = 0.5
 
     ORDERS = {
         'natural': Order(

nvitop/gui/screens/metrics.py

@@ -269,6 +269,13 @@ class ProcessMetricsScreen(Displayable):  # pylint: disable=too-many-instance-at
         self.selection.process = value
         self.enable()
 
+    @classmethod
+    def set_snapshot_interval(cls, interval):
+        assert interval > 0.0
+        interval = float(interval)
+
+        cls.SNAPSHOT_INTERVAL = min(interval / 3.0, 1.0)
+
     def take_snapshots(self):
         with self.snapshot_lock:
             if not self.selection.is_set() or not self.enabled:

nvitop/gui/screens/treeview.py

@@ -216,7 +216,7 @@ class TreeNode:  # pylint: disable=too-many-instance-attributes
 
 class TreeViewScreen(Displayable):  # pylint: disable=too-many-instance-attributes
     NAME = 'treeview'
-    SNAPSHOT_INTERVAL = 0.67
+    SNAPSHOT_INTERVAL = 0.5
 
     def __init__(self, win, root):
         super().__init__(win, root)

nvitop/gui/ui.py

@@ -77,6 +77,11 @@ class UI(DisplayableContainer):  # pylint: disable=too-many-instance-attributes
             self.add_child(self.help_screen)
 
             if interval is not None:
+                if interval < 1.0:
+                    self.main_screen.device_panel.set_snapshot_interval(interval)
+                    self.main_screen.host_panel.set_snapshot_interval(interval)
+                if interval < 0.5:
+                    self.process_metrics_screen.set_snapshot_interval(interval)
                 self.main_screen.process_panel.set_snapshot_interval(interval)
                 self.treeview_screen.set_snapshot_interval(interval)
 
@@ -190,7 +195,7 @@ class UI(DisplayableContainer):  # pylint: disable=too-many-instance-attributes
                 self.redraw()
                 self.handle_input()
                 if time.monotonic() - self.last_input_time > 1.0:
-                    time.sleep(0.25)
+                    time.sleep(0.2)
             except BreakLoop:
                 break