diff --git a/client/common_lib/cros/autoupdater.py b/client/common_lib/cros/autoupdater.py
index f94c41b..9e4b32d 100644
--- a/client/common_lib/cros/autoupdater.py
+++ b/client/common_lib/cros/autoupdater.py
@@ -167,6 +167,10 @@
             logging.info('System is already up to date. Skipping update.')
             return False
 
+        logging.info(
+            'Updating from version %s to %s.', booted_version,
+            self.update_version)
+
         # Check that Dev Server is accepting connections (from autoserv's host).
         # If we can't talk to it, the machine host probably can't either.
         auserver_host = urlparse.urlparse(self.update_url)[1]
diff --git a/server/hosts/chromiumos_host.py b/server/hosts/chromiumos_host.py
index bb7168a..5c0a692 100644
--- a/server/hosts/chromiumos_host.py
+++ b/server/hosts/chromiumos_host.py
@@ -15,15 +15,14 @@
 # Time to wait for new kernel to be marked successful.
 _KERNEL_UPDATE_TIMEOUT = 60
 
+# Ephemeral file to indicate that an update has just occurred.
+_JUST_UPDATED_FLAG = '/tmp/just_updated'
+
 
 class ChromiumOSHost(base_classes.Host):
     """ChromiumOSHost is a special subclass of SSHHost that supports
     additional install methods.
     """
-    # Force updating of the host, even if it's already up to date.
-    force_update = True
-
-
     def __initialize(self, hostname, *args, **dargs):
         """
         Construct a ChromiumOSHost object
@@ -34,7 +33,7 @@
         super(ChromiumOSHost, self)._initialize(hostname, *args, **dargs)
 
 
-    def machine_install(self, update_url=None):
+    def machine_install(self, update_url=None, force_update=False):
         if parser.options.image:
             update_url = parser.options.image
         elif not update_url:
@@ -43,7 +42,7 @@
 
         # Attempt to update the system.
         updater = autoupdater.ChromiumOSUpdater(update_url, host=self)
-        if updater.run_update(self.force_update):
+        if updater.run_update(force_update):
             # Figure out active and inactive kernel.
             active_kernel, inactive_kernel = updater.get_kernel_state()
 
@@ -92,6 +91,18 @@
                 'AUTOSERV', 'client_autodir_paths', type=list):
             self.run('rm -rf ' + path)
 
+        # Mark host as recently updated. Hosts are rebooted at the end of every
+        # test cycle which will remove the file.
+        self.run('touch %s' % _JUST_UPDATED_FLAG)
+
+
+    def has_just_updated(self):
+        """Indicates whether the host was updated within this boot."""
+        # Check for the existence of the just updated flag file.
+        return self.run(
+            '[ -f %s ] && echo T || echo F'
+            % _JUST_UPDATED_FLAG).stdout.strip() == 'T'
+
 
     def cleanup(self):
         """Special cleanup method to make sure hosts always get power back."""
diff --git a/server/site_tests/suites/control.perfalerts b/server/site_tests/suites/control.perfalerts
index b1eb882..9116763 100644
--- a/server/site_tests/suites/control.perfalerts
+++ b/server/site_tests/suites/control.perfalerts
@@ -21,6 +21,10 @@
 def run_assigned_tests(machine):
   client = hosts.create_host(machine)
 
+  # Always make sure the host has a fresh install; avoid double fresh install.
+  if not client.has_just_updated():
+      client.machine_install(force_update=True)
+
   job.run_test(
       "platform_BootPerfServer", host=client, iterations=100)