simpletrace.py

   1 #!/usr/bin/env python
   2 #
   3 # Pretty-printer for simple trace backend binary trace files
   4 #
   5 # Copyright IBM, Corp. 2010
   6 #
   7 # This work is licensed under the terms of the GNU GPL, version 2.  See
   8 # the COPYING file in the top-level directory.
   9 #
  10 # For help see docs/tracing.txt
  11
  12 import sys
  13 import struct
  14 import re
  15
  16 header_event_id = 0xffffffffffffffff
  17 header_magic    = 0xf2b177cb0aa429b4
  18 header_version  = 0
  19
  20 trace_fmt = '=QQQQQQQQ'
  21 trace_len = struct.calcsize(trace_fmt)
  22 event_re  = re.compile(r'(disable\s+)?([a-zA-Z0-9_]+)\(([^)]*)\).*')
  23
  24 def err(msg):
  25     sys.stderr.write(msg + '\n')
  26     sys.exit(1)
  27
  28 def parse_events(fobj):
  29     """Parse a trace-events file."""
  30
  31     def get_argnames(args):
  32         """Extract argument names from a parameter list."""
  33         return tuple(arg.split()[-1].lstrip('*') for arg in args.split(','))
  34
  35     events = {}
  36     event_num = 0
  37     for line in fobj:
  38         m = event_re.match(line.strip())
  39         if m is None:
  40             continue
  41
  42         disable, name, args = m.groups()
  43         events[event_num] = (name,) + get_argnames(args)
  44         event_num += 1
  45     return events
  46
  47 def read_record(fobj):
  48     """Deserialize a trace record from a file."""
  49     s = fobj.read(trace_len)
  50     if len(s) != trace_len:
  51         return None
  52     return struct.unpack(trace_fmt, s)
  53
  54 def read_trace_file(fobj):
  55     """Deserialize trace records from a file."""
  56     header = read_record(fobj)
  57     if header is None or \
  58        header[0] != header_event_id or \
  59        header[1] != header_magic or \
  60        header[2] != header_version:
  61         err('not a trace file or incompatible version')
  62
  63     while True:
  64         rec = read_record(fobj)
  65         if rec is None:
  66             break
  67
  68         yield rec
  69
  70 class Formatter(object):
  71     def __init__(self, events):
  72         self.events = events
  73         self.last_timestamp = None
  74
  75     def format_record(self, rec):
  76         if self.last_timestamp is None:
  77             self.last_timestamp = rec[1]
  78         delta_ns = rec[1] - self.last_timestamp
  79         self.last_timestamp = rec[1]
  80
  81         event = self.events[rec[0]]
  82         fields = [event[0], '%0.3f' % (delta_ns / 1000.0)]
  83         for i in xrange(1, len(event)):
  84             fields.append('%s=0x%x' % (event[i], rec[i + 1]))
  85         return ' '.join(fields)
  86
  87 if len(sys.argv) != 3:
  88     err('usage: %s <trace-events> <trace-file>' % sys.argv[0])
  89
  90 events = parse_events(open(sys.argv[1], 'r'))
  91 formatter = Formatter(events)
  92 for rec in read_trace_file(open(sys.argv[2], 'rb')):
  93     print formatter.format_record(rec)