scripts/show_delta

   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
  12 import sys
  13 import string
  14
  15 def usage():
  16         print ("""usage: show_delta [<options>] <filename>
  17
  18 This program parses the output from a set of printk message lines which
  19 have time data prefixed because the CONFIG_PRINTK_TIME option is set, or
  20 the kernel command line option "time" is specified. When run with no
  21 options, the time information is converted to show the time delta between
  22 each printk line and the next.  When run with the '-b' option, all times
  23 are relative to a single (base) point in time.
  24
  25 Options:
  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
  33 ex: $ dmesg >timefile
  34     $ show_delta -b NET4 timefile
  35
  36 will show times relative to the line in the kernel output
  37 starting 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
  44 def 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
  60 last_time = 0.0
  61 def 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
  80 def 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
 128 main()