xref: /openbmc/linux/scripts/show_delta (revision 6b342707)
1#!/usr/bin/env python
2# SPDX-License-Identifier: GPL-2.0-only
3#
4# show_deltas: Read list of printk messages instrumented with
5# time data, and format with time deltas.
6#
7# Also, you can show the times relative to a fixed point.
8#
9# Copyright 2003 Sony Corporation
10#
11
12import sys
13import string
14
15def usage():
16	print ("""usage: show_delta [<options>] <filename>
17
18This program parses the output from a set of printk message lines which
19have time data prefixed because the CONFIG_PRINTK_TIME option is set, or
20the kernel command line option "time" is specified. When run with no
21options, the time information is converted to show the time delta between
22each printk line and the next.  When run with the '-b' option, all times
23are relative to a single (base) point in time.
24
25Options:
26  -h            Show this usage help.
27  -b <base>	Specify a base for time references.
28		<base> can be a number or a string.
29		If it is a string, the first message line
30		which matches (at the beginning of the
31		line) is used as the time reference.
32
33ex: $ dmesg >timefile
34    $ show_delta -b NET4 timefile
35
36will show times relative to the line in the kernel output
37starting with "NET4".
38""")
39	sys.exit(1)
40
41# returns a tuple containing the seconds and text for each message line
42# seconds is returned as a float
43# raise an exception if no timing data was found
44def get_time(line):
45	if line[0]!="[":
46		raise ValueError
47
48	# split on closing bracket
49	(time_str, rest) = string.split(line[1:],']',1)
50	time = string.atof(time_str)
51
52	#print "time=", time
53	return (time, rest)
54
55
56# average line looks like:
57# [    0.084282] VFS: Mounted root (romfs filesystem) readonly
58# time data is expressed in seconds.useconds,
59# convert_line adds a delta for each line
60last_time = 0.0
61def convert_line(line, base_time):
62	global last_time
63
64	try:
65		(time, rest) = get_time(line)
66	except:
67		# if any problem parsing time, don't convert anything
68		return line
69
70	if base_time:
71		# show time from base
72		delta = time - base_time
73	else:
74		# just show time from last line
75		delta = time - last_time
76		last_time = time
77
78	return ("[%5.6f < %5.6f >]" % (time, delta)) + rest
79
80def main():
81	base_str = ""
82	filein = ""
83	for arg in sys.argv[1:]:
84		if arg=="-b":
85			base_str = sys.argv[sys.argv.index("-b")+1]
86		elif arg=="-h":
87			usage()
88		else:
89			filein = arg
90
91	if not filein:
92		usage()
93
94	try:
95		lines = open(filein,"r").readlines()
96	except:
97		print ("Problem opening file: %s" % filein)
98		sys.exit(1)
99
100	if base_str:
101		print ('base= "%s"' % base_str)
102		# assume a numeric base.  If that fails, try searching
103		# for a matching line.
104		try:
105			base_time = float(base_str)
106		except:
107			# search for line matching <base> string
108			found = 0
109			for line in lines:
110				try:
111					(time, rest) = get_time(line)
112				except:
113					continue
114				if string.find(rest, base_str)==1:
115					base_time = time
116					found = 1
117					# stop at first match
118					break
119			if not found:
120				print ('Couldn\'t find line matching base pattern "%s"' % base_str)
121				sys.exit(1)
122	else:
123		base_time = 0.0
124
125	for line in lines:
126		print (convert_line(line, base_time),)
127
128main()
129