Update docs for the new IRQ plugin

NEWS

@@ -19,6 +19,7 @@ Enhancements and new features:
 
     * Add Application Monitoring Process plugin (issue #780)
     * Add a new "Ports scanner" plugin (issue #734)
+    * Add a new IRQ monitoring plugin (issue #911)
     * Improve IP plugin to display public IP address (issue #646)
     * CPU additionnal stats monitoring: Context switch, Interrupts... (issue #810)
     * Filter processes by others stats (username) (issue #748)

docs/aoa/index.rst

@@ -30,6 +30,7 @@ Legend:
    disk
    fs
    folders
+   irq
    sensors
    ps
    monitor

docs/aoa/irq.rst

+.. _irq:
+
+IRQ
+===
+
+.. image:: ../_static/irq.png
+
+Glances displays the top 5 interrupts rate. This plugin is only available on
+GNU/Linux machine (stats are grabbed from the /proc/interrupts file).
+
+How to read the informations:
+
+* The first Column is the IRQ number / name
+* The Second column says how many times the CPU core has been interrupted during the last second

glances/plugins/glances_irq.py

@@ -56,12 +56,12 @@ class Plugin(GlancesPlugin):
     def update(self):
         """Update the IRQ stats"""
 
-        if not LINUX: # only available on GNU/Linux
-            return []
-
         # Reset the list
         self.reset()
 
+        if not LINUX:  # only available on GNU/Linux
+            return self.stats
+
         if self.input_method == 'local':
             with open('/proc/interrupts') as irq_proc:
                 time_since_update = getTimeSinceLastUpdate('irq')
@@ -105,7 +105,7 @@ class Plugin(GlancesPlugin):
         # Init the return message
         ret = []
 
-        if not LINUX: # only available on GNU/Linux
+        if not LINUX:  # only available on GNU/Linux
             return ret
 
         # Only process if stats exist and display plugin enable...