cpu: Add a Python-enabled traffic generator

The current traffic generator relies on a configuration file that
describes a small machine to generate stimuli. This configuration file
is usually generated by the gem5 Python configuration. This creates an
unnecessary and fragile step.

This changeset introduces a Python-based trace module. When
instantiated, the module exposes a start method that takes an iterable
object as a parameter (e.g., a generator). The iterable object is
expected to represent a list of generators that will be run one after
the other. For example:

    system.tgen = PyTrafficGen()
    m5.instantiate()

    def trace():
        yield system.tgen.createIdle(1000)
        yield system.tgen.createExit(0)

    system.tgen.start(trace())

Change-Id: I58e60ca517e86c197859f4daaa67750066abdc1c
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/11518
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

1 files changed, 71 insertions, 0 deletions

diff --git a/src/cpu/testers/traffic_gen/PyTrafficGen.py b/src/cpu/testers/traffic_gen/PyTrafficGen.py
new file mode 100644
index 000000000..c29ad0a3b
--- /dev/null
+++ b/src/cpu/testers/traffic_gen/PyTrafficGen.py
@@ -0,0 +1,71 @@
+# Copyright (c) 2018 ARM Limited
+# All rights reserved.
+#
+# The license below extends only to copyright in the software and shall
+# not be construed as granting a license to any other intellectual
+# property including but not limited to intellectual property relating
+# to a hardware implementation of the functionality of the software
+# licensed hereunder.  You may use the software subject to the license
+# terms below provided that you ensure that this notice is replicated
+# unmodified and in its entirety in all distributions of the software,
+# modified or unmodified, in source code or in binary form.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met: redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer;
+# redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution;
+# neither the name of the copyright holders nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+# Authors: Andreas Sandberg
+
+from m5.defines import buildEnv
+from m5.SimObject import *
+from BaseTrafficGen import *
+
+class PyTrafficGen(BaseTrafficGen):
+    type = 'PyTrafficGen'
+    cxx_header = "cpu/testers/traffic_gen/pygen.hh"
+
+    @cxxMethod
+    def start(self, meta_generator):
+        """
+        Start generating traffic using the provided meta-generator. The
+        meta-generator is an iterable Python object that describes a
+        list of traffic generator instances.
+        """
+        pass
+
+    cxx_exports = [
+        PyBindMethod("createIdle"),
+        PyBindMethod("createExit"),
+        PyBindMethod("createLinear"),
+        PyBindMethod("createRandom"),
+        PyBindMethod("createDram"),
+        PyBindMethod("createDramRot"),
+    ]
+
+    @cxxMethod(override=True)
+    def createTrace(self, duration, trace_file, addr_offset=0):
+        if buildEnv['HAVE_PROTOBUF']:
+            return self.getCCObject().createTrace(duration, trace_file,
+                                                  addr_offset=addr_offset)
+        else:
+            raise NotImplementedError("Trace playback requires that gem5 "
+                                      "was built with protobuf support.")