#!/usr/bin/python
  #
  # show_deltas: Read list of printk messages instrumented with
  # time data, and format with time deltas.
  #
  # Also, you can show the times relative to a fixed point.
  #
  # Copyright 2003 Sony Corporation
  #
  # GPL 2.0 applies.
  
  import sys
  import string
  
  def usage():
  	print ("""usage: show_delta [<options>] <filename>
  
  This program parses the output from a set of printk message lines which
  have time data prefixed because the CONFIG_PRINTK_TIME option is set, or
  the kernel command line option "time" is specified. When run with no
  options, the time information is converted to show the time delta between
  each printk line and the next.  When run with the '-b' option, all times
  are relative to a single (base) point in time.
  
  Options:
    -h            Show this usage help.
    -b <base>	Specify a base for time references.
  		<base> can be a number or a string.
  		If it is a string, the first message line
  		which matches (at the beginning of the
  		line) is used as the time reference.
  
  ex: $ dmesg >timefile
      $ show_delta -b NET4 timefile
  
  will show times relative to the line in the kernel output
  starting with "NET4".
  """)
  	sys.exit(1)
  
  # returns a tuple containing the seconds and text for each message line
  # seconds is returned as a float
  # raise an exception if no timing data was found
  def get_time(line):
  	if line[0]!="[":
  		raise ValueError
  
  	# split on closing bracket
  	(time_str, rest) = string.split(line[1:],']',1)
  	time = string.atof(time_str)
  
  	#print "time=", time
  	return (time, rest)
  
  
  # average line looks like:
  # [    0.084282] VFS: Mounted root (romfs filesystem) readonly
  # time data is expressed in seconds.useconds,
  # convert_line adds a delta for each line
  last_time = 0.0
  def convert_line(line, base_time):
  	global last_time
  
  	try:
  		(time, rest) = get_time(line)
  	except:
  		# if any problem parsing time, don't convert anything
  		return line
  
  	if base_time:
  		# show time from base
  		delta = time - base_time
  	else:
  		# just show time from last line
  		delta = time - last_time
  		last_time = time
  
  	return ("[%5.6f < %5.6f >]" % (time, delta)) + rest
  
  def main():
  	base_str = ""
  	filein = ""
  	for arg in sys.argv[1:]:
  		if arg=="-b":
  			base_str = sys.argv[sys.argv.index("-b")+1]
  		elif arg=="-h":
  			usage()
  		else:
  			filein = arg
  
  	if not filein:
  		usage()
  
  	try:
  		lines = open(filein,"r").readlines()
  	except:
  		print ("Problem opening file: %s" % filein)
  		sys.exit(1)
  
  	if base_str:
  		print ('base= "%s"' % base_str)
  		# assume a numeric base.  If that fails, try searching
  		# for a matching line.
  		try:
  			base_time = float(base_str)
  		except:
  			# search for line matching <base> string
  			found = 0
  			for line in lines:
  				try:
  					(time, rest) = get_time(line)
  				except:
  					continue
  				if string.find(rest, base_str)==1:
  					base_time = time
  					found = 1
  					# stop at first match
  					break
  			if not found:
  				print ('Couldn\'t find line matching base pattern "%s"' % base_str)
  				sys.exit(1)
  	else:
  		base_time = 0.0
  
  	for line in lines:
  		print (convert_line(line, base_time),)
  
  main()