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Combine the FastCall functions in cpickle. 

I fixed the bug that was in my previous attempt of this cleanup. I ran
the full test suite to verify I didn't introduce any obvious bugs.
This commit is contained in:
Alexandre Vassalotti 2013-11-27 02:26:54 -08:00
parent ba9d75e1be
commit 20c28c1ea2
1 changed files with 40 additions and 88 deletions
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128
Modules/_pickle.c
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@ -346,7 +346,6 @@ typedef struct PicklerObject {
pickling. */
PyObject *pers_func; /* persistent_id() method, can be NULL */
PyObject *dispatch_table; /* private dispatch_table, can be NULL */
PyObject *arg;
PyObject *write; /* write() method of the output stream. */
PyObject *output_buffer; /* Write into a local bytearray buffer before
@ -383,7 +382,6 @@ typedef struct UnpicklerObject {
Py_ssize_t memo_size; /* Capacity of the memo array */
Py_ssize_t memo_len; /* Number of objects in the memo */
PyObject *arg;
PyObject *pers_func; /* persistent_load() method, can be NULL. */
Py_buffer buffer;
@ -639,57 +637,37 @@ PyMemoTable_Set(PyMemoTable *self, PyObject *key, Py_ssize_t value)
/*************************************************************************/
/* Helpers for creating the argument tuple passed to functions. This has the
performance advantage of calling PyTuple_New() only once.
/* Helper for calling a function with a single argument quickly.
XXX(avassalotti): Inline directly in _Pickler_FastCall() and
_Unpickler_FastCall(). */
#define ARG_TUP(self, obj) do { \
if ((self)->arg || ((self)->arg=PyTuple_New(1))) { \
Py_XDECREF(PyTuple_GET_ITEM((self)->arg, 0)); \
PyTuple_SET_ITEM((self)->arg, 0, (obj)); \
} \
else { \
Py_DECREF((obj)); \
} \
} while (0)
This has the performance advantage of reusing the argument tuple. This
provides a nice performance boost with older pickle protocols where many
unbuffered reads occurs.
#define FREE_ARG_TUP(self) do { \
if ((self)->arg->ob_refcnt > 1) \
Py_CLEAR((self)->arg); \
} while (0)
/* A temporary cleaner API for fast single argument function call.
XXX: Does caching the argument tuple provides any real performance benefits?
A quick benchmark, on a 2.0GHz Athlon64 3200+ running Linux 2.6.24 with
glibc 2.7, tells me that it takes roughly 20,000,000 PyTuple_New(1) calls
when the tuple is retrieved from the freelist (i.e, call PyTuple_New() then
immediately DECREF it) and 1,200,000 calls when allocating brand new tuples
(i.e, call PyTuple_New() and store the returned value in an array), to save
one second (wall clock time). Either ways, the loading time a pickle stream
large enough to generate this number of calls would be massively
overwhelmed by other factors, like I/O throughput, the GC traversal and
object allocation overhead. So, I really doubt these functions provide any
real benefits.
On the other hand, oprofile reports that pickle spends a lot of time in
these functions. But, that is probably more related to the function call
overhead, than the argument tuple allocation.
XXX: And, what is the reference behavior of these? Steal, borrow? At first
glance, it seems to steal the reference of 'arg' and borrow the reference
of 'func'. */
This function steals the reference of the given argument. */
static PyObject *
_Pickler_FastCall(PicklerObject *self, PyObject *func, PyObject *arg)
_Pickle_FastCall(PyObject *func, PyObject *obj)
{
PyObject *result = NULL;
static PyObject *arg_tuple = NULL;
PyObject *result;
ARG_TUP(self, arg);
if (self->arg) {
result = PyObject_Call(func, self->arg, NULL);
FREE_ARG_TUP(self);
if (arg_tuple == NULL) {
arg_tuple = PyTuple_New(1);
if (arg_tuple == NULL) {
Py_DECREF(obj);
return NULL;
}
}
assert(arg_tuple->ob_refcnt == 1);
assert(PyTuple_GET_ITEM(arg_tuple, 0) == NULL);
PyTuple_SET_ITEM(arg_tuple, 0, obj);
result = PyObject_Call(func, arg_tuple, NULL);
Py_CLEAR(PyTuple_GET_ITEM(arg_tuple, 0));
if (arg_tuple->ob_refcnt > 1) {
/* The function called saved a reference to our argument tuple.
This means we cannot reuse it anymore. */
Py_CLEAR(arg_tuple);
}
return result;
}
@ -787,7 +765,7 @@ _Pickler_FlushToFile(PicklerObject *self)
if (output == NULL)
return -1;
result = _Pickler_FastCall(self, self->write, output);
result = _Pickle_FastCall(self->write, output);
Py_XDECREF(result);
return (result == NULL) ? -1 : 0;
}
@ -853,7 +831,6 @@ _Pickler_New(void)
self->pers_func = NULL;
self->dispatch_table = NULL;
self->arg = NULL;
self->write = NULL;
self->proto = 0;
self->bin = 0;
@ -922,20 +899,6 @@ _Pickler_SetOutputStream(PicklerObject *self, PyObject *file)
return 0;
}
/* See documentation for _Pickler_FastCall(). */
static PyObject *
_Unpickler_FastCall(UnpicklerObject *self, PyObject *func, PyObject *arg)
{
PyObject *result = NULL;
ARG_TUP(self, arg);
if (self->arg) {
result = PyObject_Call(func, self->arg, NULL);
FREE_ARG_TUP(self);
}
return result;
}
/* Returns the size of the input on success, -1 on failure. This takes its
own reference to `input`. */
static Py_ssize_t
@ -1006,7 +969,7 @@ _Unpickler_ReadFromFile(UnpicklerObject *self, Py_ssize_t n)
PyObject *len = PyLong_FromSsize_t(n);
if (len == NULL)
return -1;
data = _Unpickler_FastCall(self, self->read, len);
data = _Pickle_FastCall(self->read, len);
}
if (data == NULL)
return -1;
@ -1019,7 +982,7 @@ _Unpickler_ReadFromFile(UnpicklerObject *self, Py_ssize_t n)
Py_DECREF(data);
return -1;
}
prefetched = _Unpickler_FastCall(self, self->peek, len);
prefetched = _Pickle_FastCall(self->peek, len);
if (prefetched == NULL) {
if (PyErr_ExceptionMatches(PyExc_NotImplementedError)) {
/* peek() is probably not supported by the given file object */
@ -1229,7 +1192,6 @@ _Unpickler_New(void)
if (self == NULL)
return NULL;
self->arg = NULL;
self->pers_func = NULL;
self->input_buffer = NULL;
self->input_line = NULL;
@ -3172,7 +3134,7 @@ save_pers(PicklerObject *self, PyObject *obj, PyObject *func)
const char binpersid_op = BINPERSID;
Py_INCREF(obj);
pid = _Pickler_FastCall(self, func, obj);
pid = _Pickle_FastCall(func, obj);
if (pid == NULL)
return -1;
@ -3600,7 +3562,7 @@ save(PicklerObject *self, PyObject *obj, int pers_save)
}
if (reduce_func != NULL) {
Py_INCREF(obj);
reduce_value = _Pickler_FastCall(self, reduce_func, obj);
reduce_value = _Pickle_FastCall(reduce_func, obj);
}
else if (PyType_IsSubtype(type, &PyType_Type)) {
status = save_global(self, obj, NULL);
@ -3625,7 +3587,7 @@ save(PicklerObject *self, PyObject *obj, int pers_save)
PyObject *proto;
proto = PyLong_FromLong(self->proto);
if (proto != NULL) {
reduce_value = _Pickler_FastCall(self, reduce_func, proto);
reduce_value = _Pickle_FastCall(reduce_func, proto);
}
}
else {
@ -3794,7 +3756,6 @@ Pickler_dealloc(PicklerObject *self)
Py_XDECREF(self->write);
Py_XDECREF(self->pers_func);
Py_XDECREF(self->dispatch_table);
Py_XDECREF(self->arg);
Py_XDECREF(self->fast_memo);
PyMemoTable_Del(self->memo);
@ -3808,7 +3769,6 @@ Pickler_traverse(PicklerObject *self, visitproc visit, void *arg)
Py_VISIT(self->write);
Py_VISIT(self->pers_func);
Py_VISIT(self->dispatch_table);
Py_VISIT(self->arg);
Py_VISIT(self->fast_memo);
return 0;
}
@ -3820,7 +3780,6 @@ Pickler_clear(PicklerObject *self)
Py_CLEAR(self->write);
Py_CLEAR(self->pers_func);
Py_CLEAR(self->dispatch_table);
Py_CLEAR(self->arg);
Py_CLEAR(self->fast_memo);
if (self->memo != NULL) {
@ -3943,7 +3902,6 @@ _pickle_Pickler___init___impl(PicklerObject *self, PyObject *file, PyObject *pro
return NULL;
}
self->arg = NULL;
self->fast = 0;
self->fast_nesting = 0;
self->fast_memo = NULL;
@ -5208,9 +5166,9 @@ load_persid(UnpicklerObject *self)
if (pid == NULL)
return -1;
/* Ugh... this does not leak since _Unpickler_FastCall() steals the
reference to pid first. */
pid = _Unpickler_FastCall(self, self->pers_func, pid);
/* This does not leak since _Pickle_FastCall() steals the reference
to pid first. */
pid = _Pickle_FastCall(self->pers_func, pid);
if (pid == NULL)
return -1;
@ -5235,9 +5193,9 @@ load_binpersid(UnpicklerObject *self)
if (pid == NULL)
return -1;
/* Ugh... this does not leak since _Unpickler_FastCall() steals the
/* This does not leak since _Pickle_FastCall() steals the
reference to pid first. */
pid = _Unpickler_FastCall(self, self->pers_func, pid);
pid = _Pickle_FastCall(self->pers_func, pid);
if (pid == NULL)
return -1;
@ -5585,7 +5543,7 @@ do_append(UnpicklerObject *self, Py_ssize_t x)
PyObject *result;
value = self->stack->data[i];
result = _Unpickler_FastCall(self, append_func, value);
result = _Pickle_FastCall(append_func, value);
if (result == NULL) {
Pdata_clear(self->stack, i + 1);
Py_SIZE(self->stack) = x;
@ -5700,7 +5658,7 @@ load_additems(UnpicklerObject *self)
PyObject *item;
item = self->stack->data[i];
result = _Unpickler_FastCall(self, add_func, item);
result = _Pickle_FastCall(add_func, item);
if (result == NULL) {
Pdata_clear(self->stack, i + 1);
Py_SIZE(self->stack) = mark;
@ -5747,9 +5705,7 @@ load_build(UnpicklerObject *self)
PyObject *result;
/* The explicit __setstate__ is responsible for everything. */
/* Ugh... this does not leak since _Unpickler_FastCall() steals the
reference to state first. */
result = _Unpickler_FastCall(self, setstate, state);
result = _Pickle_FastCall(setstate, state);
Py_DECREF(setstate);
if (result == NULL)
return -1;
@ -6249,7 +6205,6 @@ Unpickler_dealloc(UnpicklerObject *self)
Py_XDECREF(self->peek);
Py_XDECREF(self->stack);
Py_XDECREF(self->pers_func);
Py_XDECREF(self->arg);
if (self->buffer.buf != NULL) {
PyBuffer_Release(&self->buffer);
self->buffer.buf = NULL;
@ -6272,7 +6227,6 @@ Unpickler_traverse(UnpicklerObject *self, visitproc visit, void *arg)
Py_VISIT(self->peek);
Py_VISIT(self->stack);
Py_VISIT(self->pers_func);
Py_VISIT(self->arg);
return 0;
}
@ -6284,7 +6238,6 @@ Unpickler_clear(UnpicklerObject *self)
Py_CLEAR(self->peek);
Py_CLEAR(self->stack);
Py_CLEAR(self->pers_func);
Py_CLEAR(self->arg);
if (self->buffer.buf != NULL) {
PyBuffer_Release(&self->buffer);
self->buffer.buf = NULL;
@ -6423,7 +6376,6 @@ _pickle_Unpickler___init___impl(UnpicklerObject *self, PyObject *file, int fix_i
if (self->memo == NULL)
return NULL;
self->arg = NULL;
self->proto = 0;
return Py_None;