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| author | Victor Stinner <victor.stinner@gmail.com> | 2013-11-18 20:08:39 (GMT) |
|---|---|---|
| committer | Victor Stinner <victor.stinner@gmail.com> | 2013-11-18 20:08:39 (GMT) |
| commit | 6989ba01742a556ebc790b4786ba1d4f4ef78692 (patch) | |
| tree | 6347c168555b98676ad2ef47b2dcaa57eebd7cac | |
| parent | f47981f51e5c825b71652ba05a982e7a437c9bce (diff) | |
| download | cpython-6989ba01742a556ebc790b4786ba1d4f4ef78692.zip cpython-6989ba01742a556ebc790b4786ba1d4f4ef78692.tar.gz cpython-6989ba01742a556ebc790b4786ba1d4f4ef78692.tar.bz2 | |
Issue #19581: Change the overallocation factor of _PyUnicodeWriter on Windows
On Windows, a factor of 50% gives best performances.
| -rw-r--r-- | Objects/unicodeobject.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c index b2f488d..bddfafd 100644 --- a/Objects/unicodeobject.c +++ b/Objects/unicodeobject.c @@ -13106,6 +13106,13 @@ int _PyUnicodeWriter_PrepareInternal(_PyUnicodeWriter *writer, Py_ssize_t length, Py_UCS4 maxchar) { +#ifdef MS_WINDOWS + /* On Windows, overallocate by 50% is the best factor */ +# define OVERALLOCATE_FACTOR 2 +#else + /* On Linux, overallocate by 25% is the best factor */ +# define OVERALLOCATE_FACTOR 4 +#endif Py_ssize_t newlen; PyObject *newbuffer; @@ -13121,9 +13128,10 @@ _PyUnicodeWriter_PrepareInternal(_PyUnicodeWriter *writer, if (writer->buffer == NULL) { assert(!writer->readonly); - if (writer->overallocate && newlen <= (PY_SSIZE_T_MAX - newlen / 4)) { - /* overallocate 25% to limit the number of resize */ - newlen += newlen / 4; + if (writer->overallocate + && newlen <= (PY_SSIZE_T_MAX - newlen / OVERALLOCATE_FACTOR)) { + /* overallocate to limit the number of realloc() */ + newlen += newlen / OVERALLOCATE_FACTOR; } if (newlen < writer->min_length) newlen = writer->min_length; @@ -13133,9 +13141,10 @@ _PyUnicodeWriter_PrepareInternal(_PyUnicodeWriter *writer, return -1; } else if (newlen > writer->size) { - if (writer->overallocate && newlen <= (PY_SSIZE_T_MAX - newlen / 4)) { - /* overallocate 25% to limit the number of resize */ - newlen += newlen / 4; + if (writer->overallocate + && newlen <= (PY_SSIZE_T_MAX - newlen / OVERALLOCATE_FACTOR)) { + /* overallocate to limit the number of realloc() */ + newlen += newlen / OVERALLOCATE_FACTOR; } if (newlen < writer->min_length) newlen = writer->min_length; @@ -13169,6 +13178,8 @@ _PyUnicodeWriter_PrepareInternal(_PyUnicodeWriter *writer, } _PyUnicodeWriter_Update(writer); return 0; + +#undef OVERALLOCATE_FACTOR } Py_LOCAL_INLINE(int) |