trace: Add simple built-in tracing backend
This patch adds a simple tracer which produces binary trace files. To
try out the simple backend:
$ ./configure --trace-backend=simple
$ make
After running QEMU you can pretty-print the trace:
$ ./simpletrace.py trace-events trace.log
The output of simpletrace.py looks like this:
qemu_realloc 0.699 ptr=0x24363f0 size=0x3 newptr=0x24363f0
qemu_free 0.768 ptr=0x24363f0
^ ^---- timestamp delta (us)
|____ trace event name
Signed-off-by: Stefan Hajnoczi <[email protected]>
trace: Make trace record fields 64-bit
Explicitly use 64-bit fields in trace records so that timestamps and
magic numbers work for 32-bit host builds.
Includes fixes from Prerna Saxena <[email protected]>.
Signed-off-by: Prerna Saxena <[email protected]>
Signed-off-by: Stefan Hajnoczi <[email protected]>
diff --git a/simpletrace.py b/simpletrace.py
new file mode 100755
index 0000000..c2cf168
--- /dev/null
+++ b/simpletrace.py
@@ -0,0 +1,93 @@
+#!/usr/bin/env python
+#
+# Pretty-printer for simple trace backend binary trace files
+#
+# Copyright IBM, Corp. 2010
+#
+# This work is licensed under the terms of the GNU GPL, version 2. See
+# the COPYING file in the top-level directory.
+#
+# For help see docs/tracing.txt
+
+import sys
+import struct
+import re
+
+header_event_id = 0xffffffffffffffff
+header_magic = 0xf2b177cb0aa429b4
+header_version = 0
+
+trace_fmt = '=QQQQQQQQ'
+trace_len = struct.calcsize(trace_fmt)
+event_re = re.compile(r'(disable\s+)?([a-zA-Z0-9_]+)\(([^)]*)\)\s+"([^"]*)"')
+
+def err(msg):
+ sys.stderr.write(msg + '\n')
+ sys.exit(1)
+
+def parse_events(fobj):
+ """Parse a trace-events file."""
+
+ def get_argnames(args):
+ """Extract argument names from a parameter list."""
+ return tuple(arg.split()[-1].lstrip('*') for arg in args.split(','))
+
+ events = {}
+ event_num = 0
+ for line in fobj:
+ m = event_re.match(line.strip())
+ if m is None:
+ continue
+
+ disable, name, args, fmt = m.groups()
+ events[event_num] = (name,) + get_argnames(args)
+ event_num += 1
+ return events
+
+def read_record(fobj):
+ """Deserialize a trace record from a file."""
+ s = fobj.read(trace_len)
+ if len(s) != trace_len:
+ return None
+ return struct.unpack(trace_fmt, s)
+
+def read_trace_file(fobj):
+ """Deserialize trace records from a file."""
+ header = read_record(fobj)
+ if header is None or \
+ header[0] != header_event_id or \
+ header[1] != header_magic or \
+ header[2] != header_version:
+ err('not a trace file or incompatible version')
+
+ while True:
+ rec = read_record(fobj)
+ if rec is None:
+ break
+
+ yield rec
+
+class Formatter(object):
+ def __init__(self, events):
+ self.events = events
+ self.last_timestamp = None
+
+ def format_record(self, rec):
+ if self.last_timestamp is None:
+ self.last_timestamp = rec[1]
+ delta_ns = rec[1] - self.last_timestamp
+ self.last_timestamp = rec[1]
+
+ event = self.events[rec[0]]
+ fields = [event[0], '%0.3f' % (delta_ns / 1000.0)]
+ for i in xrange(1, len(event)):
+ fields.append('%s=0x%x' % (event[i], rec[i + 1]))
+ return ' '.join(fields)
+
+if len(sys.argv) != 3:
+ err('usage: %s <trace-events> <trace-file>' % sys.argv[0])
+
+events = parse_events(open(sys.argv[1], 'r'))
+formatter = Formatter(events)
+for rec in read_trace_file(open(sys.argv[2], 'rb')):
+ print formatter.format_record(rec)
