LXR qemu/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
  12import sys
  13import struct
  14import re
  15
  16header_event_id = 0xffffffffffffffff
  17header_magic    = 0xf2b177cb0aa429b4
  18header_version  = 0
  19
  20trace_fmt = '=QQQQQQQQ'
  21trace_len = struct.calcsize(trace_fmt)
  22event_re  = re.compile(r'(disable\s+)?([a-zA-Z0-9_]+)\(([^)]*)\).*')
  23
  24def err(msg):
  25    sys.stderr.write(msg + '\n')
  26    sys.exit(1)
  27
  28def 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
  47def 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
  54def 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
  70class 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
  87if len(sys.argv) != 3:
  88    err('usage: %s <trace-events> <trace-file>' % sys.argv[0])
  89
  90events = parse_events(open(sys.argv[1], 'r'))
  91formatter = Formatter(events)
  92for rec in read_trace_file(open(sys.argv[2], 'rb')):
  93    print formatter.format_record(rec)
  94