#!/usr/bin/env python3
# Print the top N most executed functions in QEMU using perf.
# Syntax:
# topN_perf.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_perf.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_perf.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 perf is installed
check_perf_presence = subprocess.run(["which", "perf"],
stdout=subprocess.DEVNULL)
if check_perf_presence.returncode:
sys.exit("Please install perf before running the script!")
# Insure user has previllage to run perf
check_perf_executability = subprocess.run(["perf", "stat", "ls", "/"],
stdout=subprocess.DEVNULL,
stderr=subprocess.DEVNULL)
if check_perf_executability.returncode:
sys.exit(
"""
Error:
You may not have permission to collect stats.
Consider tweaking /proc/sys/kernel/perf_event_paranoid,
which controls use of the performance events system by
unprivileged users (without CAP_SYS_ADMIN).
-1: Allow use of (almost) all events by all users
Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK
0: Disallow ftrace function tracepoint by users without CAP_SYS_ADMIN
Disallow raw tracepoint access by users without CAP_SYS_ADMIN
1: Disallow CPU event access by users without CAP_SYS_ADMIN
2: Disallow kernel profiling by users without CAP_SYS_ADMIN
To make this setting permanent, edit /etc/sysctl.conf too, e.g.:
kernel.perf_event_paranoid = -1
* Alternatively, you can run this script under sudo privileges.
"""
)
# Run perf record
perf_record = subprocess.run((["perf", "record", "--output=/tmp/perf.data"] +
command),
stdout=subprocess.DEVNULL,
stderr=subprocess.PIPE)
if perf_record.returncode:
os.unlink('/tmp/perf.data')
sys.exit(perf_record.stderr.decode("utf-8"))
# Save perf report output to /tmp/perf_report.out
with open("/tmp/perf_report.out", "w") as output:
perf_report = subprocess.run(
["perf", "report", "--input=/tmp/perf.data", "--stdio"],
stdout=output,
stderr=subprocess.PIPE)
if perf_report.returncode:
os.unlink('/tmp/perf.data')
output.close()
os.unlink('/tmp/perf_report.out')
sys.exit(perf_report.stderr.decode("utf-8"))
# Read the reported data to functions[]
functions = []
with open("/tmp/perf_report.out", "r") as data:
# Only read lines that are not comments (comments start with #)
# Only read lines that are not empty
functions = [line for line in data.readlines() if line and line[0]
!= '#' and line[0] != "\n"]
# Limit the number of top functions to "top"
number_of_top_functions = top if len(functions) > top else len(functions)
# Store the data of the top functions in top_functions[]
top_functions = functions[:number_of_top_functions]
# Print table header
print('{:>4} {:>10} {:<30} {}\n{} {} {} {}'.format('No.',
'Percentage',
'Name',
'Invoked by',
'-' * 4,
'-' * 10,
'-' * 30,
'-' * 25))
# Print top N functions
for (index, function) in enumerate(top_functions, start=1):
function_data = function.split()
function_percentage = function_data[0]
function_name = function_data[-1]
function_invoker = ' '.join(function_data[2:-2])
print('{:>4} {:>10} {:<30} {}'.format(index,
function_percentage,
function_name,
function_invoker))
# Remove intermediate files
os.unlink('/tmp/perf.data')
os.unlink('/tmp/perf_report.out')
