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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
34 import argparse
35 import os
36 import subprocess
37 import sys
38
39
40 # Parse the command line arguments
41 parser = 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
46 parser.add_argument('-n', dest='top', type=int, default=25,
47 help='Specify the number of top functions to print.')
48
49 parser.add_argument('command', type=str, nargs='+', help=argparse.SUPPRESS)
50
51 args = parser.parse_args()
52
53 # Extract the needed variables from the args
54 command = args.command
55 top = args.top
56
57 # Insure that perf is installed
58 check_perf_presence = subprocess.run(["which", "perf"],
59 stdout=subprocess.DEVNULL)
60 if check_perf_presence.returncode:
61 sys.exit("Please install perf before running the script!")
62
63 # Insure user has previllage to run perf
64 check_perf_executability = subprocess.run(["perf", "stat", "ls", "/"],
65 stdout=subprocess.DEVNULL,
66 stderr=subprocess.DEVNULL)
67 if check_perf_executability.returncode:
68 sys.exit(
69 """
70 Error:
71 You may not have permission to collect stats.
72
73 Consider tweaking /proc/sys/kernel/perf_event_paranoid,
74 which controls use of the performance events system by
75 unprivileged 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
84 To 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
92 perf_record = subprocess.run((["perf", "record", "--output=/tmp/perf.data"] +
93 command),
94 stdout=subprocess.DEVNULL,
95 stderr=subprocess.PIPE)
96 if 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
101 with 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[]
113 functions = []
114 with 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"
121 number_of_top_functions = top if len(functions) > top else len(functions)
122
123 # Store the data of the top functions in top_functions[]
124 top_functions = functions[:number_of_top_functions]
125
126 # Print table header
127 print('{:>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
137 for (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
148 os.unlink('/tmp/perf.data')
149 os.unlink('/tmp/perf_report.out')