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gh-103793: Defer formatting task name #103767

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Merged
gvanrossum merged 14 commits into from
Apr 29, 2023
Merged

gh-103793: Defer formatting task name #103767

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e8353cc
Defer formatting task name
itamaro Apr 24, 2023
1822ff8
Defer task name formatting also in Python Task impl
itamaro Apr 24, 2023
74d0084
Add NEWS and whatsnew entries
itamaro Apr 24, 2023
dbc7047
Merge branch 'main' into defer-task-name-formatting
ambv Apr 25, 2023
2bb6c1e
Merge branch 'main' into defer-task-name-formatting
itamaro Apr 25, 2023
2efd376
replace storing the task counter on task construction with just getti…
itamaro Apr 25, 2023
6cb321b
Merge branch 'defer-task-name-formatting' of github.com:itamaro/cpyth…
itamaro Apr 25, 2023
7cde290
remove redundant return
itamaro Apr 25, 2023
4b50646
Merge branch 'main' into defer-task-name-formatting
itamaro Apr 25, 2023
a155190
revert changes to python version
itamaro Apr 25, 2023
fb2bd7f
pass error up if PyUnicode_FromFormat returns NULL
itamaro Apr 25, 2023
41e9a59
Switch back to original "assign task number at construction" but stor…
itamaro Apr 26, 2023
712edf9
Add test that using an explicit PyLong as task name does not accident…
itamaro Apr 26, 2023
592d44b
Merge branch 'main' into defer-task-name-formatting
itamaro Apr 26, 2023
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Defer formatting task name 
The default task name is "Task-<counter>" (if no name is passed in during Task creation).
This is initialized in `Task.__init__` (C impl) using string formatting, which can be quite slow.
Actually using the task name in real world code is not very common, so this is wasted init.

Let's defer this string formatting to the first time the name is read (in `get_name` impl),
so we don't need to pay the string formatting cost if the task name is never read.
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@itamaro
itamaro committed Apr 24, 2023
commit e8353cca99e57427b8d86295e249a313331f7c58
16 changes: 14 additions & 2 deletions Modules/_asynciomodule.c
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Original file line number Diff line number Diff line change
Expand Up @@ -129,6 +129,7 @@ typedef struct {
int task_must_cancel;
int task_log_destroy_pending;
int task_num_cancels_requested;
uint64_t task_name_counter;
} TaskObj;

typedef struct {
Expand Down Expand Up @@ -2065,12 +2066,16 @@ _asyncio_Task___init___impl(TaskObj *self, PyObject *coro, PyObject *loop,
self->task_must_cancel = 0;
self->task_log_destroy_pending = 1;
self->task_num_cancels_requested = 0;
self->task_name_counter = 0;
Py_INCREF(coro);
Py_XSETREF(self->task_coro, coro);

if (name == Py_None) {
name = PyUnicode_FromFormat("Task-%" PRIu64,
++state->task_name_counter);
// optimization: defer task name formatting
// set task_name to None to indicate deferred formatting, and
// store the task name counter for formatting in get_name impl
Py_INCREF(name);
self->task_name_counter = ++state->task_name_counter;
} else if (!PyUnicode_CheckExact(name)) {
name = PyObject_Str(name);
} else {
Expand Down Expand Up @@ -2449,6 +2454,13 @@ _asyncio_Task_get_name_impl(TaskObj *self)
/*[clinic end generated code: output=0ecf1570c3b37a8f input=a4a6595d12f4f0f8]*/
{
if (self->task_name) {
if (Py_IsNone(self->task_name)) {
assert(self->task_name_counter > 0);
PyObject *name = PyUnicode_FromFormat(
"Task-%" PRIu64, self->task_name_counter);
Py_XSETREF(self->task_name, name);
return Py_NewRef(self->task_name);
}
return Py_NewRef(self->task_name);
}

Expand Down