linux/scripts/show_delta
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   1#!/usr/bin/python
   2#
   3# show_deltas: Read list of printk messages instrumented with
   4# time data, and format with time deltas.
   5#
   6# Also, you can show the times relative to a fixed point.
   7#
   8# Copyright 2003 Sony Corporation
   9#
  10# GPL 2.0 applies.
  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
 130
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