scripts/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 struct
  13 import re
  14 import inspect
  15
  16 header_event_id = 0xffffffffffffffff
  17 header_magic    = 0xf2b177cb0aa429b4
  18 header_version  = 0
  19 dropped_event_id = 0xfffffffffffffffe
  20
  21 trace_fmt = '=QQQQQQQQ'
  22 trace_len = struct.calcsize(trace_fmt)
  23 event_re  = re.compile(r'(disable\s+)?([a-zA-Z0-9_]+)\(([^)]*)\).*')
  24
  25 def parse_events(fobj):
  26     """Parse a trace-events file into {event_num: (name, arg1, ...)}."""
  27
  28     def get_argnames(args):
  29         """Extract argument names from a parameter list."""
  30         return tuple(arg.split()[-1].lstrip('*') for arg in args.split(','))
  31
  32     events = {dropped_event_id: ('dropped', 'count')}
  33     event_num = 0
  34     for line in fobj:
  35         m = event_re.match(line.strip())
  36         if m is None:
  37             continue
  38
  39         disable, name, args = m.groups()
  40         events[event_num] = (name,) + get_argnames(args)
  41         event_num += 1
  42     return events
  43
  44 def read_record(fobj):
  45     """Deserialize a trace record from a file into a tuple (event_num, timestamp, arg1, ..., arg6)."""
  46     s = fobj.read(trace_len)
  47     if len(s) != trace_len:
  48         return None
  49     return struct.unpack(trace_fmt, s)
  50
  51 def read_trace_file(fobj):
  52     """Deserialize trace records from a file, yielding record tuples (event_num, timestamp, arg1, ..., arg6)."""
  53     header = read_record(fobj)
  54     if header is None or \
  55        header[0] != header_event_id or \
  56        header[1] != header_magic or \
  57        header[2] != header_version:
  58         raise ValueError('not a trace file or incompatible version')
  59
  60     while True:
  61         rec = read_record(fobj)
  62         if rec is None:
  63             break
  64
  65         yield rec
  66
  67 class Analyzer(object):
  68     """A trace file analyzer which processes trace records.
  69
  70     An analyzer can be passed to run() or process().  The begin() method is
  71     invoked, then each trace record is processed, and finally the end() method
  72     is invoked.
  73
  74     If a method matching a trace event name exists, it is invoked to process
  75     that trace record.  Otherwise the catchall() method is invoked."""
  76
  77     def begin(self):
  78         """Called at the start of the trace."""
  79         pass
  80
  81     def catchall(self, event, rec):
  82         """Called if no specific method for processing a trace event has been found."""
  83         pass
  84
  85     def end(self):
  86         """Called at the end of the trace."""
  87         pass
  88
  89 def process(events, log, analyzer):
  90     """Invoke an analyzer on each event in a log."""
  91     if isinstance(events, str):
  92         events = parse_events(open(events, 'r'))
  93     if isinstance(log, str):
  94         log = open(log, 'rb')
  95
  96     def build_fn(analyzer, event):
  97         fn = getattr(analyzer, event[0], None)
  98         if fn is None:
  99             return analyzer.catchall
 100
 101         event_argcount = len(event) - 1
 102         fn_argcount = len(inspect.getargspec(fn)[0]) - 1
 103         if fn_argcount == event_argcount + 1:
 104             # Include timestamp as first argument
 105             return lambda _, rec: fn(*rec[1:2 + fn_argcount])
 106         else:
 107             # Just arguments, no timestamp
 108             return lambda _, rec: fn(*rec[2:2 + fn_argcount])
 109
 110     analyzer.begin()
 111     fn_cache = {}
 112     for rec in read_trace_file(log):
 113         event_num = rec[0]
 114         event = events[event_num]
 115         if event_num not in fn_cache:
 116             fn_cache[event_num] = build_fn(analyzer, event)
 117         fn_cache[event_num](event, rec)
 118     analyzer.end()
 119
 120 def run(analyzer):
 121     """Execute an analyzer on a trace file given on the command-line.
 122
 123     This function is useful as a driver for simple analysis scripts.  More
 124     advanced scripts will want to call process() instead."""
 125     import sys
 126
 127     if len(sys.argv) != 3:
 128         sys.stderr.write('usage: %s <trace-events> <trace-file>\n' % sys.argv[0])
 129         sys.exit(1)
 130
 131     events = parse_events(open(sys.argv[1], 'r'))
 132     process(events, sys.argv[2], analyzer)
 133
 134 if __name__ == '__main__':
 135     class Formatter(Analyzer):
 136         def __init__(self):
 137             self.last_timestamp = None
 138
 139         def catchall(self, event, rec):
 140             timestamp = rec[1]
 141             if self.last_timestamp is None:
 142                 self.last_timestamp = timestamp
 143             delta_ns = timestamp - self.last_timestamp
 144             self.last_timestamp = timestamp
 145
 146             fields = [event[0], '%0.3f' % (delta_ns / 1000.0)]
 147             for i in xrange(1, len(event)):
 148                 fields.append('%s=0x%x' % (event[i], rec[i + 1]))
 149             print ' '.join(fields)
 150
 151     run(Formatter())