xref: /qemu/scripts/performance/topN_perf.py (revision 8b7b9c5c) 
1#!/usr/bin/env python3
2
3#  Print the top N most executed functions in QEMU using perf.
4#  Syntax:
5#  topN_perf.py [-h] [-n] <number of displayed top functions>  -- \
6#           <qemu executable> [<qemu executable options>] \
7#           <target executable> [<target executable options>]
8#
9#  [-h] - Print the script arguments help message.
10#  [-n] - Specify the number of top functions to print.
11#       - If this flag is not specified, the tool defaults to 25.
12#
13#  Example of usage:
14#  topN_perf.py -n 20 -- qemu-arm coulomb_double-arm
15#
16#  This file is a part of the project "TCG Continuous Benchmarking".
17#
18#  Copyright (C) 2020  Ahmed Karaman <ahmedkhaledkaraman@gmail.com>
19#  Copyright (C) 2020  Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>
20#
21#  This program is free software: you can redistribute it and/or modify
22#  it under the terms of the GNU General Public License as published by
23#  the Free Software Foundation, either version 2 of the License, or
24#  (at your option) any later version.
25#
26#  This program is distributed in the hope that it will be useful,
27#  but WITHOUT ANY WARRANTY; without even the implied warranty of
28#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
29#  GNU General Public License for more details.
30#
31#  You should have received a copy of the GNU General Public License
32#  along with this program. If not, see <https://www.gnu.org/licenses/>.
33
34import argparse
35import os
36import subprocess
37import sys
38
39
40# Parse the command line arguments
41parser = argparse.ArgumentParser(
42    usage='topN_perf.py [-h] [-n] <number of displayed top functions >  -- '
43          '<qemu executable> [<qemu executable options>] '
44          '<target executable> [<target executable options>]')
45
46parser.add_argument('-n', dest='top', type=int, default=25,
47                    help='Specify the number of top functions to print.')
48
49parser.add_argument('command', type=str, nargs='+', help=argparse.SUPPRESS)
50
51args = parser.parse_args()
52
53# Extract the needed variables from the args
54command = args.command
55top = args.top
56
57# Insure that perf is installed
58check_perf_presence = subprocess.run(["which", "perf"],
59                                     stdout=subprocess.DEVNULL)
60if check_perf_presence.returncode:
61    sys.exit("Please install perf before running the script!")
62
63# Insure user has previllage to run perf
64check_perf_executability = subprocess.run(["perf", "stat", "ls", "/"],
65                                          stdout=subprocess.DEVNULL,
66                                          stderr=subprocess.DEVNULL)
67if check_perf_executability.returncode:
68    sys.exit(
69"""
70Error:
71You may not have permission to collect stats.
72
73Consider tweaking /proc/sys/kernel/perf_event_paranoid,
74which controls use of the performance events system by
75unprivileged users (without CAP_SYS_ADMIN).
76
77  -1: Allow use of (almost) all events by all users
78      Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK
79   0: Disallow ftrace function tracepoint by users without CAP_SYS_ADMIN
80      Disallow raw tracepoint access by users without CAP_SYS_ADMIN
81   1: Disallow CPU event access by users without CAP_SYS_ADMIN
82   2: Disallow kernel profiling by users without CAP_SYS_ADMIN
83
84To make this setting permanent, edit /etc/sysctl.conf too, e.g.:
85   kernel.perf_event_paranoid = -1
86
87* Alternatively, you can run this script under sudo privileges.
88"""
89)
90
91# Run perf record
92perf_record = subprocess.run((["perf", "record", "--output=/tmp/perf.data"] +
93                              command),
94                             stdout=subprocess.DEVNULL,
95                             stderr=subprocess.PIPE)
96if perf_record.returncode:
97    os.unlink('/tmp/perf.data')
98    sys.exit(perf_record.stderr.decode("utf-8"))
99
100# Save perf report output to /tmp/perf_report.out
101with open("/tmp/perf_report.out", "w") as output:
102    perf_report = subprocess.run(
103        ["perf", "report", "--input=/tmp/perf.data", "--stdio"],
104        stdout=output,
105        stderr=subprocess.PIPE)
106    if perf_report.returncode:
107        os.unlink('/tmp/perf.data')
108        output.close()
109        os.unlink('/tmp/perf_report.out')
110        sys.exit(perf_report.stderr.decode("utf-8"))
111
112# Read the reported data to functions[]
113functions = []
114with open("/tmp/perf_report.out", "r") as data:
115    # Only read lines that are not comments (comments start with #)
116    # Only read lines that are not empty
117    functions = [line for line in data.readlines() if line and line[0]
118                 != '#' and line[0] != "\n"]
119
120# Limit the number of top functions to "top"
121number_of_top_functions = top if len(functions) > top else len(functions)
122
123# Store the data of the top functions in top_functions[]
124top_functions = functions[:number_of_top_functions]
125
126# Print table header
127print('{:>4}  {:>10}  {:<30}  {}\n{}  {}  {}  {}'.format('No.',
128                                                         'Percentage',
129                                                         'Name',
130                                                         'Invoked by',
131                                                         '-' * 4,
132                                                         '-' * 10,
133                                                         '-' * 30,
134                                                         '-' * 25))
135
136# Print top N functions
137for (index, function) in enumerate(top_functions, start=1):
138    function_data = function.split()
139    function_percentage = function_data[0]
140    function_name = function_data[-1]
141    function_invoker = ' '.join(function_data[2:-2])
142    print('{:>4}  {:>10}  {:<30}  {}'.format(index,
143                                             function_percentage,
144                                             function_name,
145                                             function_invoker))
146
147# Remove intermediate files
148os.unlink('/tmp/perf.data')
149os.unlink('/tmp/perf_report.out')
150