Track CPU usage (#21)

Track CPU usage

Author: yuvipanda

nbresuse/__init__.py

@@ -1,46 +1,98 @@
 import os
 import json
 import psutil
-from traitlets import Float, Int, Union, default
+from traitlets import Bool, Float, Int, Union, default
 from traitlets.config import Configurable
 from notebook.utils import url_path_join
 from notebook.base.handlers import IPythonHandler
 from tornado import web
+
 try:
     # Traitlets >= 4.3.3
     from traitlets import Callable
 except ImportError:
-    from .callable import Callable
+    from .utils import Callable
 
+from concurrent.futures import ThreadPoolExecutor
+from tornado.concurrent import run_on_executor
 
 class MetricsHandler(IPythonHandler):
+    def initialize(self):
+        super().initialize()
+        self.cpu_percent = 0
+        
+        # https://www.tornadoweb.org/en/stable/concurrent.html#tornado.concurrent.run_on_executor
+        self.executor = ThreadPoolExecutor(max_workers=10)
+
+        self.cpu_count = psutil.cpu_count()
+
+    @run_on_executor
+    def update_cpu_percent(self, all_processes):
+
+        def get_cpu_percent(p):
+            try:
+                return p.cpu_percent(interval=0.05)
+            # Avoid littering logs with stack traces complaining
+            # about dead processes having no CPU usage
+            except:
+                return 0
+
+        return sum([get_cpu_percent(p) for p in all_processes])
+
     @web.authenticated
-    def get(self):
+    async def get(self):
         """
         Calculate and return current resource usage metrics
         """
         config = self.settings['nbresuse_display_config']
         cur_process = psutil.Process()
-        all_processes = [cur_process] + cur_process.children(recursive=True)
+        all_processes = [cur_process] + cur_process.children(recursive=True)     
+        limits = {}
+
+        # Get memory information
         rss = sum([p.memory_info().rss for p in all_processes])
 
         if callable(config.mem_limit):
             mem_limit = config.mem_limit(rss=rss)
         else: # mem_limit is an Int
             mem_limit = config.mem_limit
 
-        limits = {}
+        # A better approach would use cpu_affinity to account for the
+        # fact that the number of logical CPUs in the system is not
+        # necessarily the same as the number of CPUs the process
+        # can actually use. But cpu_affinity isn't available for OS X.
+        cpu_count = psutil.cpu_count()
+
+        if config.track_cpu_percent:
+            self.cpu_percent = await self.update_cpu_percent(all_processes)
 
         if config.mem_limit != 0:
             limits['memory'] = {
                 'rss': mem_limit
             }
             if config.mem_warning_threshold != 0:
-                limits['memory']['warn'] = (config.mem_limit - rss) < (config.mem_limit * config.mem_warning_threshold)
+                limits['memory']['warn'] = (mem_limit - rss) < (mem_limit * config.mem_warning_threshold)
+
+        # Optionally get CPU information
+        if config.track_cpu_percent:
+            self.cpu_percent = await self.update_cpu_percent(all_processes)
+
+            if config.cpu_limit != 0:
+                limits['cpu'] = {
+                    'cpu': config.cpu_limit
+                }
+                if config.cpu_warning_threshold != 0:
+                    limits['cpu']['warn'] = (config.cpu_limit - self.cpu_percent) < (config.cpu_limit * config.cpu_warning_threshold)
+
         metrics = {
             'rss': rss,
             'limits': limits,
         }
+        if config.track_cpu_percent:
+            metrics.update(cpu_percent=self.cpu_percent,
+                               cpu_count=self.cpu_count)
+
+        self.log.debug("NBResuse metrics: %s", metrics)
         self.write(json.dumps(metrics))
 
 
@@ -69,7 +121,7 @@ class ResourceUseDisplay(Configurable):
     """
 
     mem_warning_threshold = Float(
-        0.1,
+        default_value=0.1,
         help="""
         Warn user with flashing lights when memory usage is within this fraction
         memory limit.
@@ -83,7 +135,6 @@ class ResourceUseDisplay(Configurable):
 
     mem_limit = Union(
         trait_types=[Int(), Callable()],
-        0,
         help="""
         Memory limit to display to the user, in bytes.
         Can also be a function which calculates the memory limit.
@@ -99,6 +150,42 @@ class ResourceUseDisplay(Configurable):
     def _mem_limit_default(self):
         return int(os.environ.get('MEM_LIMIT', 0))
 
+    track_cpu_percent = Bool(
+        default_value=False,
+        help="""
+        Set to True in order to enable reporting of CPU usage statistics.
+        """
+    ).tag(config=True)
+
+    cpu_warning_threshold = Float(
+        default_value=0.1,
+        help="""
+        Warn user with flashing lights when CPU usage is within this fraction
+        CPU usage limit.
+
+        For example, if CPU limit is 150%, `cpu_warning_threshold` is 0.1,
+        we will start warning the user when they use (150 - (150 * 0.1)) %.
+
+        Set to 0 to disable warning.
+        """
+    ).tag(config=True)
+
+    cpu_limit = Float(
+        default_value=0,
+        help="""
+        CPU usage limit to display to the user.
+
+        Note that this does not actually limit the user's CPU usage!
+
+        Defaults to reading from the `CPU_LIMIT` environment variable. If
+        set to 0, no CPU usage limit is displayed.
+        """
+    ).tag(config=True)
+
+    @default('cpu_limit')
+    def _cpu_limit_default(self):
+        return float(os.environ.get('CPU_LIMIT', 0))
+
 def load_jupyter_server_extension(nbapp):
     """
     Called during notebook start