tests: make pg_start() wait until pg completes

A sizable number of tests call pg_start() to get the packets flowing and then
immediately expect to have the entirety of the packets gone through.
This works on powerful and unstressed hardware, but fails in beautifully random
ways under load.

This also necessitates the complicated logic of remembering the "zombie captures",
then sleeping for some time before cleaning them up....

The solution is simple: in pg_start(), start the generators, wait till they
all finish, clean up, done.

Signed-off-by: Andrew Yourtchenko <ayourtch@gmail.com>
Change-Id: I930e51b7aae39c9841d22dd905a4d13a465a672b
Type: test

1 files changed, 13 insertions, 19 deletions

diff --git a/test/framework.py b/test/framework.py
index 4cdbf3488f9..fb1446572ee 100644
--- a/test/framework.py
+++ b/test/framework.py
@@ -517,7 +517,6 @@ class VppTestCase(unittest.TestCase):
         cls.setUpConstants()
         cls.reset_packet_infos()
         cls._captures = []
-        cls._zombie_captures = []
         cls.verbose = 0
         cls.vpp_dead = False
         cls.registry = VppObjectRegistry()
@@ -740,29 +739,24 @@ class VppTestCase(unittest.TestCase):
         """ Register a capture in the testclass """
         # add to the list of captures with current timestamp
         cls._captures.append((time.time(), cap_name))
-        # filter out from zombies
-        cls._zombie_captures = [(stamp, name)
-                                for (stamp, name) in cls._zombie_captures
-                                if name != cap_name]
 
     @classmethod
     def pg_start(cls):
-        """ Remove any zombie captures and enable the packet generator """
-        # how long before capture is allowed to be deleted - otherwise vpp
-        # crashes - 100ms seems enough (this shouldn't be needed at all)
-        capture_ttl = 0.1
-        now = time.time()
-        for stamp, cap_name in cls._zombie_captures:
-            wait = stamp + capture_ttl - now
-            if wait > 0:
-                cls.sleep(wait, "before deleting capture %s" % cap_name)
-                now = time.time()
-            cls.logger.debug("Removing zombie capture %s" % cap_name)
-            cls.vapi.cli('packet-generator delete %s' % cap_name)
-
+        """ Enable the PG, wait till it is done, then clean up """
         cls.vapi.cli("trace add pg-input 1000")
         cls.vapi.cli('packet-generator enable')
-        cls._zombie_captures = cls._captures
+        # PG, when starts, runs to completion -
+        # so let's avoid a race condition,
+        # and wait a little till it's done.
+        # Then clean it up  - and then be gone.
+        deadline = time.time() + 300
+        while cls.vapi.cli('show packet-generator').find("Yes") != -1:
+            cls.sleep(0.01)  # yield
+            if time.time() > deadline:
+                cls.logger.error("Timeout waiting for pg to stop")
+                break
+        for stamp, cap_name in cls._captures:
+            cls.vapi.cli('packet-generator delete %s' % cap_name)
         cls._captures = []
 
     @classmethod