fix: cpu_percent - initialization timer bugs

fixes #2859

glances/cpu_percent.py

@@ -8,16 +8,42 @@
 
 """CPU percent stats shared between CPU and Quicklook plugins."""
 
+from typing import List, Optional, TypedDict
+
 import psutil
 
 from glances.logger import logger
 from glances.timer import Timer
 
+__all__ = ["cpu_percent"]
+
+
+class CpuInfo(TypedDict):
+    cpu_name: str
+    cpu_hz: Optional[float]
+    cpu_hz_current: Optional[float]
+
+
+class PerCpuPercentInfo(TypedDict):
+    key: str
+    cpu_number: int
+    total: float
+    user: float
+    system: float
+    idle: float
+    nice: Optional[float]
+    iowait: Optional[float]
+    irq: Optional[float]
+    softirq: Optional[float]
+    steal: Optional[float]
+    guest: Optional[float]
+    guest_nice: Optional[float]
+
 
 class CpuPercent:
     """Get and store the CPU percent."""
 
-    def __init__(self, cached_timer_cpu=2):
+    def __init__(self, cached_timer_cpu: int = 2):
         # cached_timer_cpu is the minimum time interval between stats updates
         # since last update is passed (will retrieve old cached info instead)
         self.cached_timer_cpu = cached_timer_cpu
@@ -27,21 +53,21 @@ class CpuPercent:
 
         # Get CPU name
         self.timer_cpu_info = Timer(0)
-        self.cpu_info = {'cpu_name': self.__get_cpu_name(), 'cpu_hz_current': None, 'cpu_hz': None}
+        self.cpu_info: CpuInfo = {'cpu_name': self.__get_cpu_name(), 'cpu_hz_current': None, 'cpu_hz': None}
 
         # Warning from PsUtil documentation
         # The first time this function is called with interval = 0.0 or None
         # it will return a meaningless 0.0 value which you are supposed to ignore.
         self.timer_cpu = Timer(0)
-        self.cpu_percent = self.get_cpu()
+        self.cpu_percent = self._compute_cpu()
         self.timer_percpu = Timer(0)
-        self.percpu_percent = self.get_percpu()
+        self.percpu_percent = self._compute_percpu()
 
     def get_key(self):
         """Return the key of the per CPU list."""
         return 'cpu_number'
 
-    def get_info(self):
+    def get_info(self) -> CpuInfo:
         """Get additional information about the CPU"""
         # Never update more than 1 time per cached_timer_cpu_info
         if self.timer_cpu_info.finished() and hasattr(psutil, 'cpu_freq'):
@@ -63,70 +89,67 @@ class CpuPercent:
                 self.timer_cpu_info.reset(duration=self.cached_timer_cpu_info)
         return self.cpu_info
 
-    def __get_cpu_name(self):
+    @staticmethod
+    def __get_cpu_name() -> str:
         # Get the CPU name once from the /proc/cpuinfo file
         # Read the first line with the "model name" ("Model" for Raspberry Pi)
-        ret = None
         try:
-            cpuinfo_file = open('/proc/cpuinfo').readlines()
+            cpuinfo_lines = open('/proc/cpuinfo').readlines()
         except (FileNotFoundError, PermissionError):
-            pass
+            logger.debug("No permission to read '/proc/cpuinfo'")
-        else:
+            return 'CPU'
-            for line in cpuinfo_file:
-                if line.startswith('model name') or line.startswith('Model') or line.startswith('cpu model'):
-                    ret = line.split(':')[1].strip()
-                    break
-        return ret if ret else 'CPU'
 
-    def get_cpu(self):
+        for line in cpuinfo_lines:
+            if line.startswith('model name') or line.startswith('Model') or line.startswith('cpu model'):
+                return line.split(':')[1].strip()
+
+        return 'CPU'
+
+    def get_cpu(self) -> float:
         """Update and/or return the CPU using the psutil library."""
         # Never update more than 1 time per cached_timer_cpu
         if self.timer_cpu.finished():
             # Reset timer for cache
             self.timer_cpu.reset(duration=self.cached_timer_cpu)
             # Update the stats
-            self.cpu_percent = psutil.cpu_percent(interval=0.0)
+            self.cpu_percent = self._compute_cpu()
         return self.cpu_percent
 
-    def get_percpu(self):
+    @staticmethod
+    def _compute_cpu() -> float:
+        return psutil.cpu_percent(interval=0.0)
+
+    def get_percpu(self) -> List[PerCpuPercentInfo]:
         """Update and/or return the per CPU list using the psutil library."""
         # Never update more than 1 time per cached_timer_cpu
         if self.timer_percpu.finished():
             # Reset timer for cache
             self.timer_percpu.reset(duration=self.cached_timer_cpu)
-            # Get stats
-            percpu_percent = []
-            psutil_percpu = enumerate(psutil.cpu_times_percent(interval=0.0, percpu=True))
-            for cpu_number, cputimes in psutil_percpu:
-                cpu = {
-                    'key': self.get_key(),
-                    'cpu_number': cpu_number,
-                    'total': round(100 - cputimes.idle, 1),
-                    'user': cputimes.user,
-                    'system': cputimes.system,
-                    'idle': cputimes.idle,
-                }
-                # The following stats are for API purposes only
-                if hasattr(cputimes, 'nice'):
-                    cpu['nice'] = cputimes.nice
-                if hasattr(cputimes, 'iowait'):
-                    cpu['iowait'] = cputimes.iowait
-                if hasattr(cputimes, 'irq'):
-                    cpu['irq'] = cputimes.irq
-                if hasattr(cputimes, 'softirq'):
-                    cpu['softirq'] = cputimes.softirq
-                if hasattr(cputimes, 'steal'):
-                    cpu['steal'] = cputimes.steal
-                if hasattr(cputimes, 'guest'):
-                    cpu['guest'] = cputimes.guest
-                if hasattr(cputimes, 'guest_nice'):
-                    cpu['guest_nice'] = cputimes.guest_nice
-                # Append new CPU to the list
-                percpu_percent.append(cpu)
             # Update stats
-            self.percpu_percent = percpu_percent
+            self.percpu_percent = self._compute_percpu()
         return self.percpu_percent
 
+    def _compute_percpu(self) -> List[PerCpuPercentInfo]:
+        psutil_percpu = enumerate(psutil.cpu_times_percent(interval=0.0, percpu=True))
+        return [
+            {
+                'key': self.get_key(),
+                'cpu_number': cpu_number,
+                'total': round(100 - cpu_times.idle, 1),
+                'user': cpu_times.user,
+                'system': cpu_times.system,
+                'idle': cpu_times.idle,
+                'nice': cpu_times.nice if hasattr(cpu_times, 'nice') else None,
+                'iowait': cpu_times.iowait if hasattr(cpu_times, 'iowait') else None,
+                'irq': cpu_times.irq if hasattr(cpu_times, 'irq') else None,
+                'softirq': cpu_times.softirq if hasattr(cpu_times, 'softirq') else None,
+                'steal': cpu_times.steal if hasattr(cpu_times, 'steal') else None,
+                'guest': cpu_times.guest if hasattr(cpu_times, 'guest') else None,
+                'guest_nice': cpu_times.steal if hasattr(cpu_times, 'guest_nice') else None,
+            }
+            for cpu_number, cpu_times in psutil_percpu
+        ]
+
 
 # CpuPercent instance shared between plugins
 cpu_percent = CpuPercent()

glances/plugins/percpu/__init__.py

@@ -78,7 +78,6 @@ guest operating systems under the control of the Linux kernel.',
     },
 }
 
-
 # Define the history items list
 items_history_list = [
     {'name': 'user', 'description': 'User CPU usage', 'y_unit': '%'},
@@ -142,7 +141,10 @@ class PluginModel(GlancesPluginModel):
             return ret
 
         # Define the default header
-        header = ['user', 'system', 'idle', 'iowait', 'steal']
+        all_headers = ['user', 'system', 'idle', 'iowait', 'steal']
+
+        # Determine applicable headers
+        header = [h for h in all_headers if self.stats[0].get(h) is not None]
 
         # Build the string message
         if self.is_disabled('quicklook'):
@@ -152,8 +154,6 @@ class PluginModel(GlancesPluginModel):
 
         # Per CPU stats displayed per line
         for stat in header:
-            if stat not in self.stats[0]:
-                continue
             msg = f'{stat:>7}'
             ret.append(self.curse_add_line(msg))
 
@@ -179,8 +179,6 @@ class PluginModel(GlancesPluginModel):
                     msg = '{:4} '.format('?')
                 ret.append(self.curse_add_line(msg))
             for stat in header:
-                if stat not in self.stats[0]:
-                    continue
                 try:
                     msg = f'{cpu[stat]:6.1f}%'
                 except TypeError:
@@ -192,12 +190,10 @@ class PluginModel(GlancesPluginModel):
             ret.append(self.curse_new_line())
             if self.is_disabled('quicklook'):
                 ret.append(self.curse_add_line('CPU* '))
+
             for stat in header:
-                if stat not in self.stats[0]:
+                percpu_stats = [i[stat] for i in percpu_list[0 : self.max_cpu_display]]
-                    continue
+                cpu_stat = sum(percpu_stats) / len(percpu_stats)
-                cpu_stat = sum([i[stat] for i in percpu_list[0 : self.max_cpu_display]]) / len(
-                    [i[stat] for i in percpu_list[0 : self.max_cpu_display]]
-                )
                 try:
                     msg = f'{cpu_stat:6.1f}%'
                 except TypeError: