gem5/util/encode_packet_trace.py

#!/usr/bin/env python

# Copyright (c) 2013 ARM Limited
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# Copyright 2008 Google Inc.  All rights reserved.
# http://code.google.com/p/protobuf/
#
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# 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 Google Inc. 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 Hansson
#

# This script is used to migrate ASCII packet traces to the protobuf
# format currently used in gem5. It assumes that protoc has been
# executed and already generated the Python package for the packet
# messages. This can be done manually using:
# protoc --python_out=. --proto_path=src/proto src/proto/packet.proto
#
# The ASCII trace format uses one line per request on the format cmd,
# addr, size, tick. For example:
# r,128,64,4000
# w,232123,64,500000
# This trace reads 64 bytes from decimal address 128 at tick 4000,
# then writes 64 bytes to address 232123 at tick 500000.
#
# This script can of course also be used as a template to convert
# other trace formats into the gem5 protobuf format

import struct
import sys
import packet_pb2

def EncodeVarint(out_file, value):
  """
  The encoding of the Varint32 is copied from
  google.protobuf.internal.encoder and is only repeated here to
  avoid depending on the internal functions in the library.
  """
  bits = value & 0x7f
  value >>= 7
  while value:
    out_file.write(struct.pack('<B', 0x80|bits))
    bits = value & 0x7f
    value >>= 7
  out_file.write(struct.pack('<B', bits))

def encodeMessage(out_file, message):
    """
    Encoded a message with the length prepended as a 32-bit varint.
    """
    out = message.SerializeToString()
    EncodeVarint(out_file, len(out))
    out_file.write(out)

def main():
    if len(sys.argv) != 3:
        print "Usage: ", sys.argv[0], " <ASCII input> <protobuf output>"
        exit(-1)

    try:
        ascii_in = open(sys.argv[1], 'r')
    except IOError:
        print "Failed to open ", sys.argv[1], " for reading"
        exit(-1)

    try:
        proto_out = open(sys.argv[2], 'wb')
    except IOError:
        print "Failed to open ", sys.argv[2], " for writing"
        exit(-1)

    # Write the magic number in 4-byte Little Endian, similar to what
    # is done in src/proto/protoio.cc
    proto_out.write("gem5")

    # Add the packet header
    header = packet_pb2.PacketHeader()
    header.obj_id = "Converted ASCII trace " + sys.argv[1]
    # Assume the default tick rate
    header.tick_freq = 1000000000
    encodeMessage(proto_out, header)

    # For each line in the ASCII trace, create a packet message and
    # write it to the encoded output
    for line in ascii_in:
        cmd, addr, size, tick = line.split(',')
        packet = packet_pb2.Packet()
        packet.tick = long(tick)
        # ReadReq is 1 and WriteReq is 4 in src/mem/packet.hh Command enum
        packet.cmd = 1 if cmd == 'r' else 4
        packet.addr = long(addr)
        packet.size = int(size)
        encodeMessage(proto_out, packet)

    # We're done
    ascii_in.close()
    proto_out.close()

if __name__ == "__main__":
    main()