Add new timing mechanism to ftrace.

systrace/systrace/tracing_agents/ftrace_agent.py

Index: systrace/systrace/tracing_agents/ftrace_agent.py
diff --git a/systrace/systrace/tracing_agents/ftrace_agent.py b/systrace/systrace/tracing_agents/ftrace_agent.py
index 9e241eb15094ac74a3f07c44ba8340a0082efa6e..30b6f4c68a0a62b2c532b6c8b7e618fd739ecf39 100644
--- a/systrace/systrace/tracing_agents/ftrace_agent.py
+++ b/systrace/systrace/tracing_agents/ftrace_agent.py
@@ -4,7 +4,6 @@
 
 import os
 import sys
-import time
 
 from systrace import tracing_agents
 
@@ -110,13 +109,6 @@ class FtraceAgent(tracing_agents.TracingAgent):
       buffer_size = self._options.trace_buf_size
     return buffer_size
 
-  def _get_trace_time(self):
-    wait_time = 5
-    if ((self._options.trace_time is not None)
-        and (self._options.trace_time > 0)):
-      wait_time = self._options.trace_time
-    return wait_time
-
   def StartAgentTracing(self, options, categories, timeout):
     """Start tracing.
     """
@@ -148,9 +140,6 @@ class FtraceAgent(tracing_agents.TracingAgent):
       self._fio.writeFile(FT_TRACE_ON, '1')
 
   def StopAgentTracing(self, timeout):
-    pass
-
-  def GetResults(self, timeout):
     """Collect the result of tracing.
 
     This function will block while collecting the result. For sync mode, it
@@ -160,10 +149,6 @@ class FtraceAgent(tracing_agents.TracingAgent):
     if self._options.list_categories or len(self._categories) == 0:
       self._print_avail_categories()
     else:
-      try:
-        time.sleep(self._get_trace_time())
-      except KeyboardInterrupt:
-        pass
       self._fio.writeFile(FT_TRACE_ON, '0')
       for category in self._categories:
         self._category_disable(category)
@@ -174,6 +159,7 @@ class FtraceAgent(tracing_agents.TracingAgent):
       if self._options.fix_circular:
         print "WARN: circular buffer fixups are not yet supported."
 
+  def GetResults(self, timeout):
     # get the output

[charliea (OOO until 10-5), 2016/04/06 18:42:51]

nit: delete this comment (the function name makes it redundant)

     d = self._fio.readFile(FT_TRACE)
     self._fio.writeFile(FT_BUFFER_SIZE, "1")