[Qemu-devel] [PATCH v7 3/3] Update simpletrace.py for new log format

[Harsh Prateek Bora <harsh@linux.vnet.ibm.com>]

Support new tracelog format for multiple arguments and strings.

Signed-off-by: Harsh Prateek Bora <harsh@linux.vnet.ibm.com>
---
 scripts/simpletrace.py |  116 +++++++++++++++++++++++++++++++-----------------
 1 file changed, 75 insertions(+), 41 deletions(-)

diff --git a/scripts/simpletrace.py b/scripts/simpletrace.py
index f55e5e6..9b4419f 100755
--- a/scripts/simpletrace.py
+++ b/scripts/simpletrace.py
@@ -12,53 +12,69 @@
 import struct
 import re
 import inspect
+from tracetool import _read_events, Event
+from tracetool.backend.simple import is_string
 
 header_event_id = 0xffffffffffffffff
 header_magic    = 0xf2b177cb0aa429b4
-header_version  = 0
 dropped_event_id = 0xfffffffffffffffe
 
-trace_fmt = '=QQQQQQQQ'
-trace_len = struct.calcsize(trace_fmt)
-event_re  = re.compile(r'(disable\s+)?([a-zA-Z0-9_]+)\(([^)]*)\).*')
+log_header_fmt = '=QQQ'
+rec_header_fmt = '=QQII'
 
-def parse_events(fobj):
-    """Parse a trace-events file into {event_num: (name, arg1, ...)}."""
-
-    def get_argnames(args):
-        """Extract argument names from a parameter list."""
-        return tuple(arg.split()[-1].lstrip('*') for arg in args.split(','))
-
-    events = {dropped_event_id: ('dropped', 'count')}
-    event_num = 0
-    for line in fobj:
-        m = event_re.match(line.strip())
-        if m is None:
-            continue
-
-        disable, name, args = m.groups()
-        events[event_num] = (name,) + get_argnames(args)
-        event_num += 1
-    return events
+def read_header(fobj, hfmt):
+    '''Read a trace record header'''
+    hlen = struct.calcsize(hfmt)
+    hdr = fobj.read(hlen)
+    if len(hdr) != hlen:
+        return None
+    return struct.unpack(hfmt, hdr)
 
-def read_record(fobj):
+def get_record(edict, rechdr, fobj):
     """Deserialize a trace record from a file into a tuple (event_num, timestamp, arg1, ..., arg6)."""
-    s = fobj.read(trace_len)
-    if len(s) != trace_len:
+    if rechdr is None:
         return None
-    return struct.unpack(trace_fmt, s)
+    rec = (rechdr[0], rechdr[1])
+    if rechdr[0] != dropped_event_id:
+        event_id = rechdr[0]
+        event = edict[event_id]
+        for type, name in event.args:
+            if is_string(type):
+                l = fobj.read(4)
+                (len,) = struct.unpack('=L', l)
+                s = fobj.read(len)
+                rec = rec + (s,)
+            else:
+                (value,) = struct.unpack('=Q', fobj.read(8))
+                rec = rec + (value,)
+    else:
+        (value,) = struct.unpack('=Q', fobj.read(8))
+        rec = rec + (value,)
+    return rec
+
+
+def read_record(edict, fobj):
+    """Deserialize a trace record from a file into a tuple (event_num, timestamp, arg1, ..., arg6)."""
+    rechdr = read_header(fobj, rec_header_fmt)
+    return get_record(edict, rechdr, fobj) # return tuple of record elements
 
-def read_trace_file(fobj):
+def read_trace_file(edict, fobj):
     """Deserialize trace records from a file, yielding record tuples (event_num, timestamp, arg1, ..., arg6)."""
-    header = read_record(fobj)
+    header = read_header(fobj, log_header_fmt)
     if header is None or \
        header[0] != header_event_id or \
-       header[1] != header_magic or \
-       header[2] != header_version:
-        raise ValueError('not a trace file or incompatible version')
+       header[1] != header_magic:
+        raise ValueError('Not a valid trace file!')
+    if header[2] != 0 and \
+       header[2] != 2:
+        raise ValueError('Unknown version of tracelog format!')
+
+    log_version = header[2]
+    if log_version == 0:
+        raise ValueError('Older log format, not supported with this Qemu release!')
 
     while True:
-        rec = read_record(fobj)
+        rec = read_record(edict, fobj)
         if rec is None:
             break
 
@@ -89,16 +105,29 @@ class Analyzer(object):
 def process(events, log, analyzer):
     """Invoke an analyzer on each event in a log."""
     if isinstance(events, str):
-        events = parse_events(open(events, 'r'))
+        events = _read_events(open(events, 'r'))
     if isinstance(log, str):
         log = open(log, 'rb')
 
+    enabled_events = []
+    dropped_event = Event.build("Dropped_Event(uint64_t num_events_dropped)")
+    edict = {dropped_event_id: dropped_event}
+
+    for e in events:
+        if 'disable' not in e.properties:
+            enabled_events.append(e)
+    for num, event in enumerate(enabled_events):
+        edict[num] = event
+
     def build_fn(analyzer, event):
-        fn = getattr(analyzer, event[0], None)
+        if isinstance(event, str):
+            return analyzer.catchall
+
+        fn = getattr(analyzer, event.name, None)
         if fn is None:
             return analyzer.catchall
 
-        event_argcount = len(event) - 1
+        event_argcount = len(event.args)
         fn_argcount = len(inspect.getargspec(fn)[0]) - 1
         if fn_argcount == event_argcount + 1:
             # Include timestamp as first argument
@@ -109,9 +138,9 @@ def process(events, log, analyzer):
 
     analyzer.begin()
     fn_cache = {}
-    for rec in read_trace_file(log):
+    for rec in read_trace_file(edict, log):
         event_num = rec[0]
-        event = events[event_num]
+        event = edict[event_num]
         if event_num not in fn_cache:
             fn_cache[event_num] = build_fn(analyzer, event)
         fn_cache[event_num](event, rec)
@@ -128,7 +157,7 @@ def run(analyzer):
         sys.stderr.write('usage: %s <trace-events> <trace-file>\n' % sys.argv[0])
         sys.exit(1)
 
-    events = parse_events(open(sys.argv[1], 'r'))
+    events = _read_events(open(sys.argv[1], 'r'))
     process(events, sys.argv[2], analyzer)
 
 if __name__ == '__main__':
@@ -137,15 +166,20 @@ if __name__ == '__main__':
             self.last_timestamp = None
 
         def catchall(self, event, rec):
+            i = 1
             timestamp = rec[1]
             if self.last_timestamp is None:
                 self.last_timestamp = timestamp
             delta_ns = timestamp - self.last_timestamp
             self.last_timestamp = timestamp
 
-            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]))
+            fields = [event.name, '%0.3f' % (delta_ns / 1000.0)]
+            for type, name in event.args:
+                if is_string(type):
+                    fields.append('%s=%s' % (name, rec[i + 1]))
+                else:
+                    fields.append('%s=0x%x' % (name, rec[i + 1]))
+                i += 1
             print ' '.join(fields)
 
     run(Formatter())
-- 
1.7.10.4