[Kimchi-devel] [PATCH] Stop collecting background stats

[Christy Perez]

Kimchi was taking up CPU cycles when no one was using it. In order
to reduce CPU overhead, only collect information when someone has
called the get_list function.

Signed-off-by: Christy Perez <christy at linux.vnet.ibm.com>
---
 src/kimchi/model/vms.py | 39 ++++++++++++++++++++-------------------
 1 file changed, 20 insertions(+), 19 deletions(-)

diff --git a/src/kimchi/model/vms.py b/src/kimchi/model/vms.py
index b5fdb12..0117fb0 100644
--- a/src/kimchi/model/vms.py
+++ b/src/kimchi/model/vms.py
@@ -81,16 +81,12 @@ def __init__(self, **kargs):
         self.conn = kargs['conn']
         self.objstore = kargs['objstore']
         self.caps = CapabilitiesModel(**kargs)
-        self.guests_stats_thread = BackgroundTask(GUESTS_STATS_INTERVAL,
-                                                  self._update_guests_stats)
-        self.guests_stats_thread.start()
-
-    def _update_guests_stats(self):
-        vm_list = self.get_list()
-
-        for name in vm_list:
+   
+    @staticmethod 
+    def _update_guests_stats(names, conn):
+        for name in names:
             try:
-                dom = VMModel.get_vm(name, self.conn)
+                dom = VMModel.get_vm(name, conn)
 
                 vm_uuid = dom.UUIDString()
                 info = dom.info()
@@ -108,16 +104,17 @@ def _update_guests_stats(self):
                 seconds = timestamp - prevStats.get('timestamp', 0)
                 stats[vm_uuid].update({'timestamp': timestamp})
 
-                self._get_percentage_cpu_usage(vm_uuid, info, seconds)
-                self._get_network_io_rate(vm_uuid, dom, seconds)
-                self._get_disk_io_rate(vm_uuid, dom, seconds)
+                VMsModel._get_percentage_cpu_usage(vm_uuid, info, seconds)
+                VMsModel._get_network_io_rate(vm_uuid, dom, seconds)
+                VMsModel._get_disk_io_rate(vm_uuid, dom, seconds)
             except Exception as e:
                 # VM might be deleted just after we get the list.
                 # This is OK, just skip.
                 kimchi_log.debug('Error processing VM stats: %s', e.message)
                 continue
 
-    def _get_percentage_cpu_usage(self, vm_uuid, info, seconds):
+    @staticmethod
+    def _get_percentage_cpu_usage(vm_uuid, info, seconds):
         prevCpuTime = stats[vm_uuid].get('cputime', 0)
 
         cpus = info[3]
@@ -128,7 +125,8 @@ def _get_percentage_cpu_usage(self, vm_uuid, info, seconds):
 
         stats[vm_uuid].update({'cputime': info[4], 'cpu': percentage})
 
-    def _get_network_io_rate(self, vm_uuid, dom, seconds):
+    @staticmethod
+    def _get_network_io_rate(vm_uuid, dom, seconds):
         prevNetRxKB = stats[vm_uuid].get('netRxKB', 0)
         prevNetTxKB = stats[vm_uuid].get('netTxKB', 0)
         currentMaxNetRate = stats[vm_uuid].get('max_net_io', 100)
@@ -155,7 +153,8 @@ def _get_network_io_rate(self, vm_uuid, dom, seconds):
         stats[vm_uuid].update({'net_io': rate, 'max_net_io': max_net_io,
                                'netRxKB': netRxKB, 'netTxKB': netTxKB})
 
-    def _get_disk_io_rate(self, vm_uuid, dom, seconds):
+    @staticmethod
+    def _get_disk_io_rate(vm_uuid, dom, seconds):
         prevDiskRdKB = stats[vm_uuid].get('diskRdKB', 0)
         prevDiskWrKB = stats[vm_uuid].get('diskWrKB', 0)
         currentMaxDiskRate = stats[vm_uuid].get('max_disk_io', 100)
@@ -249,13 +248,15 @@ def create(self, params):
         return name
 
     def get_list(self):
-        return self.get_vms(self.conn)
+        return VMsModel.get_vms(self.conn)
 
     @staticmethod
     def get_vms(conn):
-        conn = conn.get()
-        names = [dom.name().decode('utf-8') for dom in conn.listAllDomains(0)]
-        return sorted(names, key=unicode.lower)
+        conn_ = conn.get()
+        names = [dom.name().decode('utf-8') for dom in conn_.listAllDomains(0)]
+        names = sorted(names, key=unicode.lower)
+        VMsModel._update_guests_stats(names, conn)
+        return names
 
 
 class VMModel(object):
-- 
2.1.0