scripts/performance: Add topN_callgrind.py script

#!/usr/bin/env python3

#  Print the top N most executed functions in QEMU using callgrind.

#  Syntax:

#  topN_callgrind.py [-h] [-n] <number of displayed top functions>  -- \

#           <qemu executable> [<qemu executable options>] \

#           <target executable> [<target execurable options>]

#

#  [-h] - Print the script arguments help message.

#  [-n] - Specify the number of top functions to print.

#       - If this flag is not specified, the tool defaults to 25.

#

#  Example of usage:

#  topN_callgrind.py -n 20 -- qemu-arm coulomb_double-arm

#

#  This file is a part of the project "TCG Continuous Benchmarking".

#

#  Copyright (C) 2020  Ahmed Karaman <ahmedkhaledkaraman@gmail.com>

#  Copyright (C) 2020  Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>

#

#  This program is free software: you can redistribute it and/or modify

#  it under the terms of the GNU General Public License as published by

#  the Free Software Foundation, either version 2 of the License, or

#  (at your option) any later version.

#

#  This program is distributed in the hope that it will be useful,

#  but WITHOUT ANY WARRANTY; without even the implied warranty of

#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

#  GNU General Public License for more details.

#

#  You should have received a copy of the GNU General Public License

#  along with this program. If not, see <https://www.gnu.org/licenses/>.

import argparse

import os

import subprocess

import sys

# Parse the command line arguments

parser = argparse.ArgumentParser(

    usage='topN_callgrind.py [-h] [-n] <number of displayed top functions>  -- '

          '<qemu executable> [<qemu executable options>] '

          '<target executable> [<target executable options>]')

parser.add_argument('-n', dest='top', type=int, default=25,

                    help='Specify the number of top functions to print.')

parser.add_argument('command', type=str, nargs='+', help=argparse.SUPPRESS)

args = parser.parse_args()

# Extract the needed variables from the args

command = args.command

top = args.top

# Insure that valgrind is installed

check_valgrind_presence = subprocess.run(["which", "valgrind"],

                                         stdout=subprocess.DEVNULL)

if check_valgrind_presence.returncode:

    sys.exit("Please install valgrind before running the script!")

# Run callgrind

callgrind = subprocess.run((

    ["valgrind", "--tool=callgrind", "--callgrind-out-file=/tmp/callgrind.data"]

    + command),

    stdout=subprocess.DEVNULL,

    stderr=subprocess.PIPE)

if callgrind.returncode:

    sys.exit(callgrind.stderr.decode("utf-8"))

# Save callgrind_annotate output to /tmp/callgrind_annotate.out

with open("/tmp/callgrind_annotate.out", "w") as output:

    callgrind_annotate = subprocess.run(["callgrind_annotate",

                                         "/tmp/callgrind.data"],

                                        stdout=output,

                                        stderr=subprocess.PIPE)

    if callgrind_annotate.returncode:

        os.unlink('/tmp/callgrind.data')

        output.close()

        os.unlink('/tmp/callgrind_annotate.out')

        sys.exit(callgrind_annotate.stderr.decode("utf-8"))

# Read the callgrind_annotate output to callgrind_data[]

callgrind_data = []

with open('/tmp/callgrind_annotate.out', 'r') as data:

    callgrind_data = data.readlines()

# Line number with the total number of instructions

total_instructions_line_number = 20

# Get the total number of instructions

total_instructions_line_data = callgrind_data[total_instructions_line_number]

total_number_of_instructions = total_instructions_line_data.split(' ')[0]

total_number_of_instructions = int(

    total_number_of_instructions.replace(',', ''))

# Line number with the top function

first_func_line = 25

# Number of functions recorded by callgrind, last two lines are always empty

number_of_functions = len(callgrind_data) - first_func_line - 2

# Limit the number of top functions to "top"

number_of_top_functions = (top if number_of_functions >

                           top else number_of_functions)

# Store the data of the top functions in top_functions[]

top_functions = callgrind_data[first_func_line:

                               first_func_line + number_of_top_functions]

# Print table header

print('{:>4}  {:>10}  {:<30}  {}\n{}  {}  {}  {}'.format('No.',

                                                         'Percentage',

                                                         'Function Name',

                                                         'Source File',

                                                         '-' * 4,

                                                         '-' * 10,

                                                         '-' * 30,

                                                         '-' * 30,

                                                         ))

# Print top N functions

for (index, function) in enumerate(top_functions, start=1):

    function_data = function.split()

    # Calculate function percentage

    function_instructions = float(function_data[0].replace(',', ''))

    function_percentage = (function_instructions /

                           total_number_of_instructions)*100

    # Get function name and source files path

    function_source_file, function_name = function_data[1].split(':')

    # Print extracted data

    print('{:>4}  {:>9.3f}%  {:<30}  {}'.format(index,

                                                round(function_percentage, 3),

                                                function_name,

                                                function_source_file))

# Remove intermediate files

os.unlink('/tmp/callgrind.data')

os.unlink('/tmp/callgrind_annotate.out')