840d835177
The simpletrace.py script can pretty-print flight recorder ring buffers. These are not full simpletrace binary trace files but just the end of a trace file. There is no header and the event ID mapping information is often unavailable since the ring buffer may have filled up and discarded event ID mapping records. The simpletrace.stp script that generates ring buffer traces uses the same trace-events-all input file as simpletrace.py. Therefore both scripts have the same global ordering of trace events. A dynamic event ID mapping isn't necessary: just use the trace-events-all file as the reference for how event IDs are numbered. It is now possible to analyze simpletrace.stp ring buffers again using: $ ./simpletrace.py trace-events-all path/to/ring-buffer Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170815084430.7128-3-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
263 lines
8.4 KiB
Python
Executable File
263 lines
8.4 KiB
Python
Executable File
#!/usr/bin/env python
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#
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# Pretty-printer for simple trace backend binary trace files
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#
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# Copyright IBM, Corp. 2010
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#
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# This work is licensed under the terms of the GNU GPL, version 2. See
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# the COPYING file in the top-level directory.
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#
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# For help see docs/devel/tracing.txt
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import struct
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import re
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import inspect
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from tracetool import read_events, Event
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from tracetool.backend.simple import is_string
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header_event_id = 0xffffffffffffffff
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header_magic = 0xf2b177cb0aa429b4
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dropped_event_id = 0xfffffffffffffffe
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record_type_mapping = 0
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record_type_event = 1
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log_header_fmt = '=QQQ'
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rec_header_fmt = '=QQII'
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def read_header(fobj, hfmt):
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'''Read a trace record header'''
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hlen = struct.calcsize(hfmt)
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hdr = fobj.read(hlen)
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if len(hdr) != hlen:
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return None
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return struct.unpack(hfmt, hdr)
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def get_record(edict, idtoname, rechdr, fobj):
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"""Deserialize a trace record from a file into a tuple
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(name, timestamp, pid, arg1, ..., arg6)."""
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if rechdr is None:
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return None
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if rechdr[0] != dropped_event_id:
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event_id = rechdr[0]
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name = idtoname[event_id]
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rec = (name, rechdr[1], rechdr[3])
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try:
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event = edict[name]
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except KeyError, e:
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import sys
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sys.stderr.write('%s event is logged but is not declared ' \
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'in the trace events file, try using ' \
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'trace-events-all instead.\n' % str(e))
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sys.exit(1)
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for type, name in event.args:
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if is_string(type):
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l = fobj.read(4)
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(len,) = struct.unpack('=L', l)
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s = fobj.read(len)
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rec = rec + (s,)
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else:
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(value,) = struct.unpack('=Q', fobj.read(8))
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rec = rec + (value,)
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else:
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rec = ("dropped", rechdr[1], rechdr[3])
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(value,) = struct.unpack('=Q', fobj.read(8))
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rec = rec + (value,)
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return rec
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def get_mapping(fobj):
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(event_id, ) = struct.unpack('=Q', fobj.read(8))
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(len, ) = struct.unpack('=L', fobj.read(4))
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name = fobj.read(len)
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return (event_id, name)
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def read_record(edict, idtoname, fobj):
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"""Deserialize a trace record from a file into a tuple (event_num, timestamp, pid, arg1, ..., arg6)."""
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rechdr = read_header(fobj, rec_header_fmt)
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return get_record(edict, idtoname, rechdr, fobj)
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def read_trace_header(fobj):
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"""Read and verify trace file header"""
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header = read_header(fobj, log_header_fmt)
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if header is None:
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raise ValueError('Not a valid trace file!')
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if header[0] != header_event_id:
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raise ValueError('Not a valid trace file, header id %d != %d' %
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(header[0], header_event_id))
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if header[1] != header_magic:
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raise ValueError('Not a valid trace file, header magic %d != %d' %
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(header[1], header_magic))
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log_version = header[2]
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if log_version not in [0, 2, 3, 4]:
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raise ValueError('Unknown version of tracelog format!')
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if log_version != 4:
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raise ValueError('Log format %d not supported with this QEMU release!'
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% log_version)
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def read_trace_records(edict, idtoname, fobj):
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"""Deserialize trace records from a file, yielding record tuples (event_num, timestamp, pid, arg1, ..., arg6).
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Note that `idtoname` is modified if the file contains mapping records.
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Args:
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edict (str -> Event): events dict, indexed by name
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idtoname (int -> str): event names dict, indexed by event ID
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fobj (file): input file
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"""
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while True:
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t = fobj.read(8)
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if len(t) == 0:
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break
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(rectype, ) = struct.unpack('=Q', t)
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if rectype == record_type_mapping:
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event_id, name = get_mapping(fobj)
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idtoname[event_id] = name
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else:
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rec = read_record(edict, idtoname, fobj)
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yield rec
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class Analyzer(object):
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"""A trace file analyzer which processes trace records.
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An analyzer can be passed to run() or process(). The begin() method is
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invoked, then each trace record is processed, and finally the end() method
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is invoked.
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If a method matching a trace event name exists, it is invoked to process
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that trace record. Otherwise the catchall() method is invoked.
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Example:
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The following method handles the runstate_set(int new_state) trace event::
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def runstate_set(self, new_state):
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...
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The method can also take a timestamp argument before the trace event
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arguments::
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def runstate_set(self, timestamp, new_state):
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...
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Timestamps have the uint64_t type and are in nanoseconds.
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The pid can be included in addition to the timestamp and is useful when
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dealing with traces from multiple processes::
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def runstate_set(self, timestamp, pid, new_state):
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...
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"""
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def begin(self):
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"""Called at the start of the trace."""
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pass
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def catchall(self, event, rec):
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"""Called if no specific method for processing a trace event has been found."""
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pass
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def end(self):
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"""Called at the end of the trace."""
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pass
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def process(events, log, analyzer, read_header=True):
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"""Invoke an analyzer on each event in a log."""
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if isinstance(events, str):
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events = read_events(open(events, 'r'))
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if isinstance(log, str):
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log = open(log, 'rb')
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if read_header:
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read_trace_header(log)
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dropped_event = Event.build("Dropped_Event(uint64_t num_events_dropped)")
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edict = {"dropped": dropped_event}
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idtoname = {dropped_event_id: "dropped"}
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for event in events:
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edict[event.name] = event
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# If there is no header assume event ID mapping matches events list
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if not read_header:
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for event_id, event in enumerate(events):
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idtoname[event_id] = event.name
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def build_fn(analyzer, event):
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if isinstance(event, str):
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return analyzer.catchall
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fn = getattr(analyzer, event.name, None)
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if fn is None:
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return analyzer.catchall
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event_argcount = len(event.args)
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fn_argcount = len(inspect.getargspec(fn)[0]) - 1
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if fn_argcount == event_argcount + 1:
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# Include timestamp as first argument
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return lambda _, rec: fn(*((rec[1:2],) + rec[3:3 + event_argcount]))
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elif fn_argcount == event_argcount + 2:
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# Include timestamp and pid
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return lambda _, rec: fn(*rec[1:3 + event_argcount])
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else:
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# Just arguments, no timestamp or pid
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return lambda _, rec: fn(*rec[3:3 + event_argcount])
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analyzer.begin()
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fn_cache = {}
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for rec in read_trace_records(edict, idtoname, log):
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event_num = rec[0]
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event = edict[event_num]
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if event_num not in fn_cache:
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fn_cache[event_num] = build_fn(analyzer, event)
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fn_cache[event_num](event, rec)
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analyzer.end()
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def run(analyzer):
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"""Execute an analyzer on a trace file given on the command-line.
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This function is useful as a driver for simple analysis scripts. More
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advanced scripts will want to call process() instead."""
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import sys
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read_header = True
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if len(sys.argv) == 4 and sys.argv[1] == '--no-header':
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read_header = False
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del sys.argv[1]
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elif len(sys.argv) != 3:
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sys.stderr.write('usage: %s [--no-header] <trace-events> ' \
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'<trace-file>\n' % sys.argv[0])
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sys.exit(1)
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events = read_events(open(sys.argv[1], 'r'))
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process(events, sys.argv[2], analyzer, read_header=read_header)
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if __name__ == '__main__':
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class Formatter(Analyzer):
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def __init__(self):
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self.last_timestamp = None
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def catchall(self, event, rec):
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timestamp = rec[1]
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if self.last_timestamp is None:
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self.last_timestamp = timestamp
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delta_ns = timestamp - self.last_timestamp
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self.last_timestamp = timestamp
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fields = [event.name, '%0.3f' % (delta_ns / 1000.0),
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'pid=%d' % rec[2]]
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i = 3
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for type, name in event.args:
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if is_string(type):
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fields.append('%s=%s' % (name, rec[i]))
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else:
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fields.append('%s=0x%x' % (name, rec[i]))
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i += 1
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print ' '.join(fields)
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run(Formatter())
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