untrackable objects are not tracked by the garbage collector. This can
reduce the size of collections and therefore the garbage collection overhead
on long-running programs, depending on their particular use of datatypes.
(trivia: this makes the "binary_trees" benchmark from the Computer Language
Shootout 40% faster)
The basic algorithm remains the same; the most significant speedups
come from the following three changes:
(1) normalize by shifting instead of multiplying and dividing
(2) the old algorithm usually did an unnecessary extra iteration of
the outer loop; remove this. As a special case, this means that
long divisions with a single-digit result run twice as fast as
before.
(3) make inner loop much tighter.
Various benchmarks show speedups of between 50% and 150% for long
integer divisions and modulo operations.
sizeof(Py_UNICODE) == 2, PyUnicode_FromWideChar now converts
each character outside the BMP to the appropriate surrogate pair.
Thanks Victor Stinner for the patch.
(backport of r70452 from py3k to trunk)
For simple uses for str.format(), this makes the typing easier. Hopfully this
will help in the adoption of str.format().
For example:
'The {} is {}'.format('sky', 'blue')
You can mix and matcth auto-numbering and named replacement fields:
'The {} is {color}'.format('sky', color='blue')
But you can't mix and match auto-numbering and specified numbering:
'The {0} is {}'.format('sky', 'blue')
ValueError: cannot switch from manual field specification to automatic field numbering
Will port to 3.1.
and cleanups in Objects/longobject.c. The most significant change is that
longs now use less memory: average savings are 2 bytes per long on 32-bit
systems and 6 bytes per long on 64-bit systems. (This memory saving already
exists in py3k.)
platforms. The previous code was fragile, depending on the twin
accidents that:
(1) in C, casting the double value 2.**63 to long returns the integer
value -2**63, and
(2) in Python, hash(-2**63) == hash(2**63).
There's already a test for this in test_hash.
- fix some places where counters into ob_digit were declared as
int instead of Py_ssize_t
- add (twodigit) casts where necessary
- fix code in _PyLong_AsByteArray that uses << on negative values
#4759: allow None as first argument of bytearray.translate(), for consistency with bytes.translate().
Also fix segfault for bytearray.translate(x, None) -- will backport this part to 3.0 and 2.6.
the __long__ slot is allowed to return either int or long, but the behaviour of
float objects should not change between 2.5 and 2.6.
Reviewed by Benjamin Peterson
exception afterwards (for a subsequent parameter), the user code will
not call PyBuffer_Release() and memory will leak.
Reviewed by Amaury Forgeot d'Arc.
match Python 2.5 speed despite the __instancecheck__ / __subclasscheck__
mechanism. In the process, fix a bug where isinstance() and issubclass(),
when given a tuple of classes as second argument, were looking up
__instancecheck__ / __subclasscheck__ on the tuple rather than on each
type object.
Reviewed by Benjamin Peterson and Raymond Hettinger.
* crashes on memory allocation failure found with failmalloc
* memory leaks found with valgrind
* compiler warnings in opt mode which would lead to invalid memory reads
* problem using wrong name in decimal module reported by pychecker
Update the valgrind suppressions file with new leaks that are small/one-time
leaks we don't care about (ie, they are too hard to fix).
TBR=barry
TESTED=./python -E -tt ./Lib/test/regrtest.py -uall (both debug and opt modes)
in opt mode:
valgrind -q --leak-check=yes --suppressions=Misc/valgrind-python.supp \
./python -E -tt ./Lib/test/regrtest.py -uall,-bsddb,-compiler \
-x test_logging test_ssl test_multiprocessing
valgrind -q --leak-check=yes --suppressions=Misc/valgrind-python.supp \
./python -E -tt ./Lib/test/regrtest.py test_multiprocessing
for i in `seq 1 4000` ; do
LD_PRELOAD=~/local/lib/libfailmalloc.so FAILMALLOC_INTERVAL=$i \
./python -c pass
done
At least some of these fixes should probably be backported to 2.5.
rewrite float.fromhex to only allow ASCII hex digits on all platforms.
(Tests for this are already present, but the test_float failures
on Solaris hadn't been noticed before.)
Reviewed by Antoine Pitrou.
Optimization of str.format() for cases with str, unicode, int, long,
and float arguments. This gives about 30% speed improvement for the
simplest (but most common) cases. This patch skips the __format__
dispatch, and also avoids creating an object to hold the format_spec.
Unfortunately there's a complication in 2.6 with int, long, and float
because they always expect str format_specs. So in the unicode
version of this optimization, just check for unicode objects. int,
float, long, and str can be added later, if needed.
Benjamin Peterson
Georg Brandl
Eric Smith
Antoine Pitrou
Mark Dickinson
Hirokazu Yamamoto
Kristján Valur Jónsson
Raymond Hettinger
Amaury Forgeot d'Arc
Martin v. Löwis
Nick Coghlan
Alexandre Vassalotti
Andrew M. Kuchling
Christian Heimes
Andrew MacIntyre
Neal Norwitz