Annotation of qemu/scripts/simpletrace.py, revision 1.1.1.3

1.1       root        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
1.1.1.2   root       14: import inspect
1.1       root       15: 
                     16: header_event_id = 0xffffffffffffffff
                     17: header_magic    = 0xf2b177cb0aa429b4
                     18: header_version  = 0
1.1.1.2   root       19: dropped_event_id = 0xfffffffffffffffe
1.1       root       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):
1.1.1.2   root       26:     """Parse a trace-events file into {event_num: (name, arg1, ...)}."""
1.1       root       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: 
1.1.1.2   root       32:     events = {dropped_event_id: ('dropped', 'count')}
1.1       root       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):
1.1.1.2   root       45:     """Deserialize a trace record from a file into a tuple (event_num, timestamp, arg1, ..., arg6)."""
1.1       root       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):
1.1.1.2   root       52:     """Deserialize trace records from a file, yielding record tuples (event_num, timestamp, arg1, ..., arg6)."""
1.1       root       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:
1.1.1.2   root       58:         raise ValueError('not a trace file or incompatible version')
1.1       root       59: 
                     60:     while True:
                     61:         rec = read_record(fobj)
                     62:         if rec is None:
                     63:             break
                     64: 
                     65:         yield rec
                     66: 
1.1.1.2   root       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
1.1.1.3 ! root      105:             return lambda _, rec: fn(*rec[1:2 + event_argcount])
1.1.1.2   root      106:         else:
                    107:             # Just arguments, no timestamp
1.1.1.3 ! root      108:             return lambda _, rec: fn(*rec[2:2 + event_argcount])
1.1.1.2   root      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())

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