250 lines
8.7 KiB
ReStructuredText
250 lines
8.7 KiB
ReStructuredText
Tracers
|
|
=======
|
|
|
|
PythonPDEVS provides several features that allow you to trace the execution of your model.
|
|
Here, we present four built-in tracers, and present the interface used to create your own tracer.
|
|
For all tracers, providing the *None* object as the filename causes the trace to be printed to stdout, instead of writing it to a file.
|
|
|
|
In the context of distributed simulation, tracing is a *destructive event*, meaning that it can only occur after the GVT.
|
|
As such, tracing happens in blocks as soon as fossil collection occurs.
|
|
|
|
Verbose
|
|
-------
|
|
|
|
The first tracer is the verbose tracer, which generates a purely textual trace of your model execution.
|
|
It has already been presented before, and was used by invoking the following configuration option::
|
|
|
|
sim.setVerbose(None)
|
|
|
|
Note that this is the only built-in tracer that works without additional configuration of the model.
|
|
An example snippet is shown below::
|
|
|
|
__ Current Time: 0.00 __________________________________________
|
|
|
|
|
|
INITIAL CONDITIONS in model <trafficSystem.trafficLight>
|
|
Initial State: red
|
|
Next scheduled internal transition at time 58.50
|
|
|
|
|
|
INITIAL CONDITIONS in model <trafficSystem.policeman>
|
|
Initial State: idle
|
|
Next scheduled internal transition at time 200.00
|
|
|
|
|
|
__ Current Time: 58.50 __________________________________________
|
|
|
|
|
|
INTERNAL TRANSITION in model <trafficSystem.trafficLight>
|
|
New State: green
|
|
Output Port Configuration:
|
|
port <OBSERVED>:
|
|
grey
|
|
Next scheduled internal transition at time 108.50
|
|
|
|
|
|
__ Current Time: 108.50 __________________________________________
|
|
|
|
|
|
INTERNAL TRANSITION in model <trafficSystem.trafficLight>
|
|
New State: yellow
|
|
Output Port Configuration:
|
|
port <OBSERVED>:
|
|
yellow
|
|
Next scheduled internal transition at time 118.50
|
|
|
|
...
|
|
|
|
__ Current Time: 200.00 __________________________________________
|
|
|
|
|
|
EXTERNAL TRANSITION in model <trafficSystem.trafficLight>
|
|
Input Port Configuration:
|
|
port <INTERRUPT>:
|
|
toManual
|
|
New State: manual
|
|
Next scheduled internal transition at time inf
|
|
|
|
|
|
INTERNAL TRANSITION in model <trafficSystem.policeman>
|
|
New State: working
|
|
Output Port Configuration:
|
|
port <OUT>:
|
|
toManual
|
|
Next scheduled internal transition at time 300.00
|
|
|
|
XML
|
|
---
|
|
|
|
The second tracer is the XML tracer, which generates an XML-structured trace of your model execution, compliant to the notation presented in `Bill Song's thesis <http://msdl.cs.mcgill.ca/people/bill/thesis/latexthesis.pdf>`_.
|
|
It can also simply be enabled by setting the following configuration option::
|
|
|
|
sim.setXML(None)
|
|
|
|
To enable this XML tracing, the model has to be augmented with facilities to dump the current state in the form of an XML notation.
|
|
This is done with the *toXML()* method, which has to be defined for all complex states, and must return a string to be embedded in the XML.
|
|
This string is pasted as-is in the trace file, and should therefore not contain forbidden characters (e.g., <).
|
|
For example, a *toXML* method for the traffic light can look as follows::
|
|
|
|
class TrafficLightMode:
|
|
...
|
|
|
|
def toXML(self):
|
|
return "<mode>%s</mode>" % self.__colour
|
|
|
|
An example snippet is shown below::
|
|
|
|
<trace>
|
|
<event>
|
|
<model>trafficSystem.trafficLight</model>
|
|
<time>0.0</time>
|
|
<kind>EX</kind>
|
|
<state>
|
|
<mode>red</mode><![CDATA[red]]>
|
|
</state>
|
|
</event>
|
|
<event>
|
|
<model>trafficSystem.policeman</model>
|
|
<time>0.0</time>
|
|
<kind>EX</kind>
|
|
<state>
|
|
<mode>idle</mode><![CDATA[idle]]>
|
|
</state>
|
|
</event>
|
|
<event>
|
|
<model>trafficSystem.trafficLight</model>
|
|
<time>58.5</time>
|
|
<kind>IN</kind>
|
|
<port name="OBSERVED" category="O">
|
|
<message>grey</message>
|
|
</port>
|
|
<state>
|
|
<mode>green</mode><![CDATA[green]]>
|
|
</state>
|
|
</event>
|
|
...
|
|
<event>
|
|
<model>trafficSystem.policeman</model>
|
|
<time>200.0</time>
|
|
<kind>IN</kind>
|
|
<port name="OUT" category="O">
|
|
<message>toManual</message>
|
|
</port>
|
|
<state>
|
|
<mode>working</mode><![CDATA[working]]>
|
|
</state>
|
|
</event>
|
|
<event>
|
|
<model>trafficSystem.trafficLight</model>
|
|
<time>200.0</time>
|
|
<kind>EX</kind>
|
|
<port name="INTERRUPT" category="I">
|
|
<message>toManual</message>
|
|
</port>
|
|
<state>
|
|
<mode>manual</mode><![CDATA[manual]]>
|
|
</state>
|
|
</event>
|
|
</trace>
|
|
|
|
|
|
VCD
|
|
---
|
|
|
|
TODO
|
|
|
|
Cell
|
|
----
|
|
|
|
The cell tracer is discussed separately, as it has very specific behaviour and is only applicable to a select number of models.
|
|
|
|
Custom
|
|
------
|
|
|
|
Additionally, it might necessary to define your own custom tracer.
|
|
This can be done by defining a class similar to the following template.
|
|
For each trace method, an *aDEVS* parameter is passed, being a reference to the atomic DEVS model doing the transition.
|
|
On this *aDEVS* object, the following functions and attributes can be accessed:
|
|
|
|
- *aDEVS.getModelFullName()*: full hierarchical name of the model
|
|
- *aDEVS.IPorts*: reference to all input ports
|
|
- *aDEVS.OPorts*: reference to all output ports
|
|
- *aDEVS.state*: state of model
|
|
- *aDEVS.time_last[0]*: Time of next transition
|
|
- *aDEVS.time_next[0]*: Time of next transition
|
|
- *aDEVS.my_output*: dictionary of output events
|
|
- *aDEVS.my_input*: dictionary of input events
|
|
- *aDEVS.elapsed*: elapsed time before transition
|
|
|
|
A custom tracer can be defined as follows::
|
|
|
|
class TracerCustom(object):
|
|
def __init__(self, uid, server, filename):
|
|
"""
|
|
Both uid and server can be ignored, as these are only required for distributed simulation
|
|
filename contains the name of the file in which we should write the trace
|
|
"""
|
|
pass
|
|
|
|
def startTracer(self, recover):
|
|
"""
|
|
Recover is a boolean representing whether or not this is a recovered call (e.g., should the file be overwritten or appended to?)
|
|
"""
|
|
pass
|
|
|
|
def stopTracer(self):
|
|
"""
|
|
Stops the tracer (e.g., flush the file)
|
|
"""
|
|
pass
|
|
|
|
def traceInternal(self, aDEVS):
|
|
"""
|
|
Called for each atomic DEVS model that does an internal transition.
|
|
"""
|
|
pass
|
|
|
|
def traceExternal(self, aDEVS):
|
|
"""
|
|
Called for each atomic DEVS model that does an external transition.
|
|
"""
|
|
pass
|
|
|
|
def traceConfluent(self, aDEVS):
|
|
"""
|
|
Called for each atomic DEVS model that does a confluent transition.
|
|
"""
|
|
pass
|
|
|
|
def traceInit(self, aDEVS, t):
|
|
"""
|
|
Called upon initialization of a model.
|
|
The parameter *t* contains the time at which the model commences (likely 0).
|
|
"""
|
|
pass
|
|
|
|
def traceUser(self, time, aDEVS, variable, value):
|
|
"""
|
|
Called upon so called *god events* during debuggin, where a user manually alters the state of an atomic DEVS instance.
|
|
"""
|
|
pass
|
|
|
|
For some "example" tracers, have a look at the built-in tracers of PythonPDEVS, which can be found in *src/tracers*.
|
|
|
|
Note that in optimistic synchronization the destructive parts of this operation should be separated.
|
|
This can be done using the *runTraceAtController* function::
|
|
|
|
runTraceAtController(server, uid, aDEVS, [time, trace_text])
|
|
|
|
Both the *server* and *uid* are those passed to the constructor of the tracer.
|
|
|
|
Finally, after the tracer is defined, it needs to be registered for the simulator to use it.
|
|
This is done using the following call on the instantiated simulator::
|
|
|
|
sim.setCustomTracer(self, tracerfile, tracerclass, args):
|
|
|
|
Where:
|
|
|
|
- *tracerfile*: the Python class containing the implementation of the tracer, which is dynamically imported.
|
|
- *tracerclass*: the name of the class implementing the tracing functionality.
|
|
- *args*: the list of arguments that must additionally be passed to the tracer (e.g., filename)
|