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bpo-37961, tracemalloc: add Traceback.total_nframe (GH-15545) 

Add a total_nframe field to the traces collected by the tracemalloc module.
This field indicates the original number of frames before it was truncated.
This commit is contained in:
Julien Danjou 2019-10-15 14:00:16 +02:00 committed by Victor Stinner
parent f3ef06a7cb
commit 8d59eb1b66
5 changed files with 114 additions and 64 deletions
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15
Doc/library/tracemalloc.rst
View File

@ -313,6 +313,9 @@ Functions
frames. By default, a trace of a memory block only stores the most recent
frame: the limit is ``1``. *nframe* must be greater or equal to ``1``.
You can still read the original number of total frames that composed the
traceback by looking at the :attr:`Traceback.total_nframe` attribute.
Storing more than ``1`` frame is only useful to compute statistics grouped
by ``'traceback'`` or to compute cumulative statistics: see the
:meth:`Snapshot.compare_to` and :meth:`Snapshot.statistics` methods.
@ -659,6 +662,9 @@ Traceback
When a snapshot is taken, tracebacks of traces are limited to
:func:`get_traceback_limit` frames. See the :func:`take_snapshot` function.
The original number of frames of the traceback is stored in the
:attr:`Traceback.total_nframe` attribute. That allows to know if a traceback
has been truncated by the traceback limit.
The :attr:`Trace.traceback` attribute is an instance of :class:`Traceback`
instance.
@ -666,6 +672,15 @@ Traceback
.. versionchanged:: 3.7
Frames are now sorted from the oldest to the most recent, instead of most recent to oldest.
.. attribute:: total_nframe
Total number of frames that composed the traceback before truncation.
This attribute can be set to ``None`` if the information is not
available.
.. versionchanged:: 3.9
The :attr:`Traceback.total_nframe` attribute was added.
.. method:: format(limit=None, most_recent_first=False)
Format the traceback as a list of lines with newlines. Use the

90
Lib/test/test_tracemalloc.py
View File

@ -36,7 +36,7 @@ def allocate_bytes(size):
bytes_len = (size - EMPTY_STRING_SIZE)
frames = get_frames(nframe, 1)
data = b'x' * bytes_len
return data, tracemalloc.Traceback(frames)
return data, tracemalloc.Traceback(frames, min(len(frames), nframe))
def create_snapshots():
traceback_limit = 2
@ -45,27 +45,27 @@ def create_snapshots():
# traceback_frames) tuples. traceback_frames is a tuple of (filename,
# line_number) tuples.
raw_traces = [
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(1, 2, (('a.py', 5), ('b.py', 4))),
(1, 2, (('a.py', 5), ('b.py', 4)), 3),
(2, 66, (('b.py', 1),)),
(2, 66, (('b.py', 1),), 1),
(3, 7, (('<unknown>', 0),)),
(3, 7, (('<unknown>', 0),), 1),
]
snapshot = tracemalloc.Snapshot(raw_traces, traceback_limit)
raw_traces2 = [
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(2, 2, (('a.py', 5), ('b.py', 4))),
(2, 5000, (('a.py', 5), ('b.py', 4))),
(2, 2, (('a.py', 5), ('b.py', 4)), 3),
(2, 5000, (('a.py', 5), ('b.py', 4)), 3),
(4, 400, (('c.py', 578),)),
(4, 400, (('c.py', 578),), 1),
]
snapshot2 = tracemalloc.Snapshot(raw_traces2, traceback_limit)
@ -125,7 +125,7 @@ class TestTracemallocEnabled(unittest.TestCase):
nframe = tracemalloc.get_traceback_limit()
frames = get_frames(nframe, -3)
obj_traceback = tracemalloc.Traceback(frames)
obj_traceback = tracemalloc.Traceback(frames, min(len(frames), nframe))
traceback = tracemalloc.get_object_traceback(obj)
self.assertIsNotNone(traceback)
@ -167,7 +167,7 @@ class TestTracemallocEnabled(unittest.TestCase):
trace = self.find_trace(traces, obj_traceback)
self.assertIsInstance(trace, tuple)
domain, size, traceback = trace
domain, size, traceback, length = trace
self.assertEqual(size, obj_size)
self.assertEqual(traceback, obj_traceback._frames)
@ -197,8 +197,8 @@ class TestTracemallocEnabled(unittest.TestCase):
trace1 = self.find_trace(traces, obj1_traceback)
trace2 = self.find_trace(traces, obj2_traceback)
domain1, size1, traceback1 = trace1
domain2, size2, traceback2 = trace2
domain1, size1, traceback1, length1 = trace1
domain2, size2, traceback2, length2 = trace2
self.assertIs(traceback2, traceback1)
def test_get_traced_memory(self):
@ -259,6 +259,9 @@ class TestTracemallocEnabled(unittest.TestCase):
# take a snapshot
snapshot = tracemalloc.take_snapshot()
# This can vary
self.assertGreater(snapshot.traces[1].traceback.total_nframe, 10)
# write on disk
snapshot.dump(support.TESTFN)
self.addCleanup(support.unlink, support.TESTFN)
@ -321,7 +324,7 @@ class TestSnapshot(unittest.TestCase):
maxDiff = 4000
def test_create_snapshot(self):
raw_traces = [(0, 5, (('a.py', 2),))]
raw_traces = [(0, 5, (('a.py', 2),), 10)]
with contextlib.ExitStack() as stack:
stack.enter_context(patch.object(tracemalloc, 'is_tracing',
@ -336,6 +339,7 @@ class TestSnapshot(unittest.TestCase):
self.assertEqual(len(snapshot.traces), 1)
trace = snapshot.traces[0]
self.assertEqual(trace.size, 5)
self.assertEqual(trace.traceback.total_nframe, 10)
self.assertEqual(len(trace.traceback), 1)
self.assertEqual(trace.traceback[0].filename, 'a.py')
self.assertEqual(trace.traceback[0].lineno, 2)
@ -351,11 +355,11 @@ class TestSnapshot(unittest.TestCase):
# exclude b.py
snapshot3 = snapshot.filter_traces((filter1,))
self.assertEqual(snapshot3.traces._traces, [
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4))),
(1, 2, (('a.py', 5), ('b.py', 4))),
(3, 7, (('<unknown>', 0),)),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(1, 2, (('a.py', 5), ('b.py', 4)), 3),
(3, 7, (('<unknown>', 0),), 1),
])
# filter_traces() must not touch the original snapshot
@ -364,10 +368,10 @@ class TestSnapshot(unittest.TestCase):
# only include two lines of a.py
snapshot4 = snapshot3.filter_traces((filter2, filter3))
self.assertEqual(snapshot4.traces._traces, [
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4))),
(1, 2, (('a.py', 5), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(1, 2, (('a.py', 5), ('b.py', 4)), 3),
])
# No filter: just duplicate the snapshot
@ -388,21 +392,21 @@ class TestSnapshot(unittest.TestCase):
# exclude a.py of domain 1
snapshot3 = snapshot.filter_traces((filter1,))
self.assertEqual(snapshot3.traces._traces, [
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4))),
(2, 66, (('b.py', 1),)),
(3, 7, (('<unknown>', 0),)),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(2, 66, (('b.py', 1),), 1),
(3, 7, (('<unknown>', 0),), 1),
])
# include domain 1
snapshot3 = snapshot.filter_traces((filter1,))
self.assertEqual(snapshot3.traces._traces, [
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4))),
(2, 66, (('b.py', 1),)),
(3, 7, (('<unknown>', 0),)),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(2, 66, (('b.py', 1),), 1),
(3, 7, (('<unknown>', 0),), 1),
])
def test_filter_traces_domain_filter(self):
@ -413,17 +417,17 @@ class TestSnapshot(unittest.TestCase):
# exclude domain 2
snapshot3 = snapshot.filter_traces((filter1,))
self.assertEqual(snapshot3.traces._traces, [
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4))),
(0, 10, (('a.py', 2), ('b.py', 4))),
(1, 2, (('a.py', 5), ('b.py', 4))),
(2, 66, (('b.py', 1),)),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(0, 10, (('a.py', 2), ('b.py', 4)), 3),
(1, 2, (('a.py', 5), ('b.py', 4)), 3),
(2, 66, (('b.py', 1),), 1),
])
# include domain 2
snapshot3 = snapshot.filter_traces((filter2,))
self.assertEqual(snapshot3.traces._traces, [
(3, 7, (('<unknown>', 0),)),
(3, 7, (('<unknown>', 0),), 1),
])
def test_snapshot_group_by_line(self):

26
Lib/tracemalloc.py
View File

@ -182,15 +182,20 @@ class Traceback(Sequence):
Sequence of Frame instances sorted from the oldest frame
to the most recent frame.
"""
__slots__ = ("_frames",)
__slots__ = ("_frames", '_total_nframe')
def __init__(self, frames):
def __init__(self, frames, total_nframe=None):
Sequence.__init__(self)
# frames is a tuple of frame tuples: see Frame constructor for the
# format of a frame tuple; it is reversed, because _tracemalloc
# returns frames sorted from most recent to oldest, but the
# Python API expects oldest to most recent
self._frames = tuple(reversed(frames))
self._total_nframe = total_nframe
@property
def total_nframe(self):
return self._total_nframe
def __len__(self):
return len(self._frames)
@ -221,7 +226,12 @@ class Traceback(Sequence):
return str(self[0])
def __repr__(self):
return "<Traceback %r>" % (tuple(self),)
s = "<Traceback %r" % tuple(self)
if self._total_nframe is None:
s += ">"
else:
s += f" total_nframe={self.total_nframe}>"
return s
def format(self, limit=None, most_recent_first=False):
lines = []
@ -280,7 +290,7 @@ class Trace:
@property
def traceback(self):
return Traceback(self._trace[2])
return Traceback(*self._trace[2:])
def __eq__(self, other):
if not isinstance(other, Trace):
@ -378,7 +388,7 @@ class Filter(BaseFilter):
return self._match_frame(filename, lineno)
def _match(self, trace):
domain, size, traceback = trace
domain, size, traceback, total_nframe = trace
res = self._match_traceback(traceback)
if self.domain is not None:
if self.inclusive:
@ -398,7 +408,7 @@ class DomainFilter(BaseFilter):
return self._domain
def _match(self, trace):
domain, size, traceback = trace
domain, size, traceback, total_nframe = trace
return (domain == self.domain) ^ (not self.inclusive)
@ -475,7 +485,7 @@ class Snapshot:
tracebacks = {}
if not cumulative:
for trace in self.traces._traces:
domain, size, trace_traceback = trace
domain, size, trace_traceback, total_nframe = trace
try:
traceback = tracebacks[trace_traceback]
except KeyError:
@ -496,7 +506,7 @@ class Snapshot:
else:
# cumulative statistics
for trace in self.traces._traces:
domain, size, trace_traceback = trace
domain, size, trace_traceback, total_nframe = trace
for frame in trace_traceback:
try:
traceback = tracebacks[frame]

2
Misc/NEWS.d/next/Library/2019-08-27-10-30-44.bpo-37961.4nm0zZ.rst Normal file
View File

@ -0,0 +1,2 @@
Add a ``total_nframe`` field to the traces collected by the tracemalloc module.
This field indicates the original number of frames before it was truncated.

45
Modules/_tracemalloc.c
View File

@ -78,15 +78,20 @@ __attribute__((packed))
typedef struct {
Py_uhash_t hash;
int nframe;
/* Number of frames stored */
uint16_t nframe;
/* Total number of frames the traceback had */
uint16_t total_nframe;
frame_t frames[1];
} traceback_t;
#define TRACEBACK_SIZE(NFRAME) \
(sizeof(traceback_t) + sizeof(frame_t) * (NFRAME - 1))
#define MAX_NFRAME \
((INT_MAX - (int)sizeof(traceback_t)) / (int)sizeof(frame_t) + 1)
/* The maximum number of frames is either:
- The maximum number of frames we can store in `traceback_t.nframe`
- The maximum memory size_t we can allocate */
static const unsigned long MAX_NFRAME = Py_MIN(UINT16_MAX, ((SIZE_MAX - sizeof(traceback_t)) / sizeof(frame_t) + 1));
static PyObject *unknown_filename = NULL;
@ -308,6 +313,9 @@ hashtable_compare_traceback(_Py_hashtable_t *ht, const void *pkey,
if (traceback1->nframe != traceback2->nframe)
return 0;
if (traceback1->total_nframe != traceback2->total_nframe)
return 0;
for (i=0; i < traceback1->nframe; i++) {
frame1 = &traceback1->frames[i];
frame2 = &traceback2->frames[i];
@ -416,6 +424,7 @@ traceback_hash(traceback_t *traceback)
/* the cast might truncate len; that doesn't change hash stability */
mult += (Py_uhash_t)(82520UL + len + len);
}
x ^= traceback->total_nframe;
x += 97531UL;
return x;
}
@ -436,11 +445,13 @@ traceback_get_frames(traceback_t *traceback)
}
for (pyframe = tstate->frame; pyframe != NULL; pyframe = pyframe->f_back) {
tracemalloc_get_frame(pyframe, &traceback->frames[traceback->nframe]);
assert(traceback->frames[traceback->nframe].filename != NULL);
traceback->nframe++;
if (traceback->nframe == _Py_tracemalloc_config.max_nframe)
break;
if (traceback->nframe < _Py_tracemalloc_config.max_nframe) {
tracemalloc_get_frame(pyframe, &traceback->frames[traceback->nframe]);
assert(traceback->frames[traceback->nframe].filename != NULL);
traceback->nframe++;
}
if (traceback->total_nframe < UINT16_MAX)
traceback->total_nframe++;
}
}
@ -456,6 +467,7 @@ traceback_new(void)
/* get frames */
traceback = tracemalloc_traceback;
traceback->nframe = 0;
traceback->total_nframe = 0;
traceback_get_frames(traceback);
if (traceback->nframe == 0)
return &tracemalloc_empty_traceback;
@ -1001,6 +1013,7 @@ tracemalloc_init(void)
PyUnicode_InternInPlace(&unknown_filename);
tracemalloc_empty_traceback.nframe = 1;
tracemalloc_empty_traceback.total_nframe = 1;
/* borrowed reference */
tracemalloc_empty_traceback.frames[0].filename = unknown_filename;
tracemalloc_empty_traceback.frames[0].lineno = 0;
@ -1046,10 +1059,10 @@ tracemalloc_start(int max_nframe)
PyMemAllocatorEx alloc;
size_t size;
if (max_nframe < 1 || max_nframe > MAX_NFRAME) {
if (max_nframe < 1 || (unsigned long) max_nframe > MAX_NFRAME) {
PyErr_Format(PyExc_ValueError,
"the number of frames must be in range [1; %i]",
(int)MAX_NFRAME);
"the number of frames must be in range [1; %lu]",
MAX_NFRAME);
return -1;
}
@ -1062,7 +1075,6 @@ tracemalloc_start(int max_nframe)
return 0;
}
assert(1 <= max_nframe && max_nframe <= MAX_NFRAME);
_Py_tracemalloc_config.max_nframe = max_nframe;
/* allocate a buffer to store a new traceback */
@ -1234,7 +1246,7 @@ trace_to_pyobject(unsigned int domain, trace_t *trace,
PyObject *trace_obj = NULL;
PyObject *obj;
trace_obj = PyTuple_New(3);
trace_obj = PyTuple_New(4);
if (trace_obj == NULL)
return NULL;
@ -1259,6 +1271,13 @@ trace_to_pyobject(unsigned int domain, trace_t *trace,
}
PyTuple_SET_ITEM(trace_obj, 2, obj);
obj = PyLong_FromUnsignedLong(trace->traceback->total_nframe);
if (obj == NULL) {
Py_DECREF(trace_obj);
return NULL;
}
PyTuple_SET_ITEM(trace_obj, 3, obj);
return trace_obj;
}