The new API allows to efficiently send values into native generators
and coroutines avoiding use of StopIteration exceptions to signal
returns.
ceval loop now uses this method instead of the old "private"
_PyGen_Send C API. This translates to 1.6x increased performance
of 'await' calls in micro-benchmarks.
Aside from CPython core improvements, this new API will also allow
Cython to generate more efficient code, benefiting high-performance
IO libraries like uvloop.
When allocating MemoryError classes, there is some logic to use
pre-allocated instances in a freelist only if the type that is being
allocated is not a subclass of MemoryError. Unfortunately in the
destructor this logic is not present so the freelist is altered even
with subclasses of MemoryError.
My mentee @xvxvxvxvxv noticed that iterating over array.array is
slightly faster than iterating over bytes. Looking at the source I
observed that arrayiter_next() calls `getitem(ao, it->index++)` wheras
striter_next() uses the idiom (paraphrased)
item = PyLong_FromLong(seq->ob_sval[it->it_index]);
if (item != NULL)
++it->it_next;
return item;
I'm not 100% sure but I think that the second version has fewer
opportunity for the CPU to overlap the `index++` operation with the
rest of the code (which in both cases involves a call). So here I am
optimistically incrementing the index -- if the PyLong_FromLong() call
fails, this will leave the iterator pointing at the next byte, but
honestly I doubt that anyone would seriously consider resuming use of
the iterator after that kind of failure (it would have to be a
MemoryError). And the author of arrayiter_next() made the same
consideration (or never ever gave it a thought :-).
With this, a loop like
for _ in b: pass
is now slightly *faster* than the same thing over an equivalent array,
rather than slightly *slower* (in both cases a few percent).
Walk down the MRO backwards to find the type that originally defined the final `tp_setattro`, then make sure we are not jumping over intermediate C-level bases with the Python-level call.
Automerge-Triggered-By: @gvanrossum
* Merge gen and frame state variables into one.
* Replace stack pointer with depth in PyFrameObject. Makes code easier to read and saves a word of memory.
* Add failing test.
* bpo-29590: fix stack trace for gen.throw() with yield from (GH-NNNN)
When gen.throw() is called on a generator after a "yield from", the
intermediate stack trace entries are lost. This commit fixes that.
Always create the empty bytes string singleton.
Optimize PyBytes_FromStringAndSize(str, 0): it no longer has to check
if the empty string singleton was created or not, it is always
available.
Add functions:
* _PyBytes_Init()
* bytes_get_empty(), bytes_new_empty()
* bytes_create_empty_string_singleton()
* unicode_create_empty_string_singleton()
_Py_unicode_state: rename empty structure member to empty_string.
Py_InitializeFromConfig() now always creates the empty tuple
singleton as soon as possible.
Optimize PyTuple_New(0): it no longer has to check if the empty tuple
was created or not, it is always creatd.
* Add tuple_create_empty_tuple_singleton() function.
* Add tuple_get_empty() function.
* Remove state parameter of tuple_alloc().
Each interpreter now has its own Unicode latin1 singletons.
Remove "ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS"
and "ifdef LATIN1_SINGLETONS": always enable latin1 singletons.
Optimize unicode_result_ready(): only attempt to get a latin1
singleton for PyUnicode_1BYTE_KIND.
Functions of unicodeobject.c, like PyUnicode_New(), no longer check
if the empty Unicode singleton has been initialized or not. Consider
that it is always initialized. The Unicode API must not be used
before _PyUnicode_Init() or after _PyUnicode_Fini().
Each interpreter now has its own MemoryError free list: it is not
longer shared by all interpreters.
Add _Py_exc_state structure and PyInterpreterState.exc_state member.
Move also errnomap into _Py_exc_state.
* Revert "bpo-40521: Make the empty frozenset per interpreter (GH-21068)"
This reverts commit 261cfedf76.
* bpo-40521: Empty frozensets are no longer singletons
* Complete the removal of the frozenset singleton
Each interpreter now has its own empty bytes string and single byte
character singletons.
Replace STRINGLIB_EMPTY macro with STRINGLIB_GET_EMPTY() macro.
Victor Stinner
Serhiy Storchaka
Vladimir Matveev
Batuhan Taskaya
Maggie Moss
dxflores
Benjamin Peterson
Pablo Galindo
Inada Naoki
Guido van Rossum
Dong-hee Na
scoder
Brett Cannon
Mark Shannon
Chris Jerdonek
stratakis
Jeong Ukjae
Raymond Hettinger