Commit Graph

18 Commits

Author SHA1 Message Date
Damien George
36c1052183 py/objtype: Optimise instance get/set/del by skipping special accessors.
This patch is a code optimisation, trading text bytes for speed.  On
pyboard it's an increase of 0.06% in code size for a gain (in pystone
performance) of roughly 6.5%.

The patch optimises load/store/delete of attributes in user defined classes
by not looking up special accessors (@property, __get__, __delete__,
__set__, __setattr__ and __getattr_) if they are guaranteed not to exist in
the class.

Currently, if you do my_obj.foo() then the runtime has to do a few checks
to see if foo is a property or has __get__, and if so delegate the call.
And for stores things like my_obj.foo = 1 has to first check if foo is a
property or has __set__ defined on it.

Doing all those checks each and every time the attribute is accessed has a
performance penalty.  This patch eliminates all those checks for cases when
it's guaranteed that the checks will always fail, ie no attributes are
properties nor have any special accessor methods defined on them.

To make this guarantee it checks all attributes of a user-defined class
when it is first created.  If any of the attributes of the user class are
properties or have special accessors, or any of the base classes of the
user class have them, then it sets a flag in the class to indicate that
special accessors must be checked for.  Then in the load/store/delete code
it checks this flag to see if it can take the shortcut and optimise the
lookup.

It's an optimisation that's pretty widely applicable because it improves
lookup performance for all methods of user defined classes, and stores of
attributes, at least for those that don't have special accessors.  And, it
allows to enable descriptors with minimal additional runtime overhead if
they are not used for a particular user class.

There is one restriction on dynamic class creation that has been introduced
by this patch: a user-defined class cannot go from zero special accessors
to one special accessor (or more) after that class has been subclassed.  If
the script attempts this an AttributeError is raised (see addition to
tests/misc/non_compliant.py for an example of this case).

The cost in code space bytes for the optimisation in this patch is:

   unix x64:  +528
unix nanbox:  +508
      stm32:  +192
     cc3200:  +200
    esp8266:  +332
      esp32:  +244

Performance tests that were done:

- on unix x86-64, pystone improved by about 5%
- on pyboard, pystone improved by about 6.5%, from 1683 up to 1794
- on pyboard, bm_chaos (from CPython benchmark suite) improved by about 5%
- on esp32, pystone improved by about 30% (but there are caching effects)
- on esp32, bm_chaos improved by about 11%
2018-06-08 12:12:08 +10:00
Damien George
36f79523ab tests: Add tests to improve coverage of py/objtype.c. 2017-12-14 12:25:30 +11:00
Damien George
2ac1364688 py/objset: Check that RHS of a binary op is a set/frozenset.
CPython docs explicitly state that the RHS of a set/frozenset binary op
must be a set to prevent user errors.  It also preserves commutativity of
the ops, eg: "abc" & set() is a TypeError, and so should be set() & "abc".

This change actually decreases unix (x64) code by 160 bytes; it increases
stm32 by 4 bytes and esp8266 by 28 bytes (but previous patch already
introduced a much large saving).
2017-10-03 17:56:27 +11:00
Paul Sokolovsky
85d809d1f4 tests: Convert remaining "sys.exit()" to "raise SystemExit". 2017-06-10 20:34:38 +03:00
Paul Sokolovsky
3e321f1724 tests/misc/: Make few tests skippable. 2017-03-11 01:17:02 +01:00
Damien George
7314ebae8a tests/misc/non_compliant: Add test for inability to assign func attrs. 2017-01-19 23:38:53 +11:00
Rami Ali
1731868ae7 tests: Add tests to improve coverage of objarray.c. 2016-12-21 18:21:41 +11:00
Damien George
e9404e5f5f tests: Improve coverage of array, range, dict, slice, exc, unicode. 2016-10-17 11:43:47 +11:00
Damien George
5e22afce41 tests: Improve test coverage of py/compile.c. 2016-10-11 12:30:32 +11:00
Damien George
82af4d6749 tests: Improve coverage of struct with test for non-compliant behaviour. 2016-10-07 12:57:25 +11:00
Damien George
b359cf2911 tests/misc/non_compliant: Add tests to improve coverage testing. 2016-08-15 10:46:46 +10:00
Doug Currie
2e2e15cec2 py/mpz: Complete implementation of mpz_{and,or,xor} for negative args.
For these 3 bitwise operations there are now fast functions for
positive-only arguments, and general functions for arbitrary sign
arguments (the fast functions are the existing implementation).

By default the fast functions are not used (to save space) and instead
the general functions are used for all operations.

Enable MICROPY_OPT_MPZ_BITWISE to use the fast functions for positive
arguments.
2016-02-03 22:13:39 +00:00
Damien George
22b2265053 py/parse: Improve constant folding to operate on small and big ints.
Constant folding in the parser can now operate on big ints, whatever
their representation.  This is now possible because the parser can create
parse nodes holding arbitrary objects.  For the case of small ints the
folding is still efficient in RAM because the folded small int is stored
inplace in the parse node.

Adds 48 bytes to code size on Thumb2 architecture.  Helps reduce heap
usage because more constants can be computed at compile time, leading to
a smaller parse tree, and most importantly means that the constants don't
have to be computed at runtime (perhaps more than once).  Parser will now
be a little slower when folding due to calls to runtime to do the
arithmetic.
2016-01-07 14:40:35 +00:00
Damien George
4c02e54298 py/mpz: Raise NotImplError instead of failing assertion. 2015-10-01 17:57:36 +01:00
Damien George
55b11e6d38 py/objstr: For str.endswith(s, start) raise NotImpl instead of assert. 2015-09-04 16:49:56 +01:00
Damien George
25afc7da0d tests: Add tests to improve coverage of objstr.c. 2015-09-03 23:06:18 +01:00
Damien George
22602cc37b py/objstr: Make str.rsplit(None,n) raise NotImpl instead of assert(0). 2015-09-01 15:35:31 +01:00
Damien George
c9fa667252 tests: Add tests for non-compliant behaviour.
These tests are intended to improve coverage and provide a record of
behaviour that's either not implemented or non-compliant to CPython.
2015-08-30 12:32:26 +01:00