CircuitPython - a Python implementation for teaching coding with microcontrollers https://git.suspectdevices.com/suspect-devices/circuitpython/atom?h=master 2018-06-08T02:12:08+00:00 2018-06-08T02:12:08+00:00 Damien George damien.p.george@gmail.com 2018-05-25T07:09:54+00:00 urn:sha1:36c105218321167d47b0fb67575a7cddc36d17e7 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% 2017-12-14T01:25:30+00:00 Damien George damien.p.george@gmail.com 2017-12-14T01:25:30+00:00 urn:sha1:36f79523abe8d79fec1cc7af41e8e96e8ceb2cc4 2017-10-03T06:56:27+00:00 Damien George damien.p.george@gmail.com 2017-10-03T06:56:27+00:00 urn:sha1:2ac1364688cd3ee313661e82a336663551986fc8 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). 2017-01-19T12:38:53+00:00 Damien George damien.p.george@gmail.com 2017-01-19T12:38:53+00:00 urn:sha1:7314ebae8a3c7fae2c61427d428593ce84b4ccb5 2016-12-21T07:21:41+00:00 Rami Ali flowergrass@users.noreply.github.com 2016-12-21T06:51:42+00:00 urn:sha1:1731868ae7a2d22e26e9ed939be18929fed81400 2016-10-17T00:43:47+00:00 Damien George damien.p.george@gmail.com 2016-10-17T00:43:47+00:00 urn:sha1:e9404e5f5f058db954ac0a92cb5acfcef6f6724a 2016-10-11T01:30:32+00:00 Damien George damien.p.george@gmail.com 2016-10-11T01:30:32+00:00 urn:sha1:5e22afce41de8c87071d8fc149a6ba3cd8762819 2016-10-07T01:57:25+00:00 Damien George damien.p.george@gmail.com 2016-10-07T01:57:25+00:00 urn:sha1:82af4d6749072d01195da647f54b79c80f1ad731 2016-08-15T00:46:46+00:00 Damien George damien.p.george@gmail.com 2016-08-15T00:46:46+00:00 urn:sha1:b359cf2911781120f5c866107734269435c4e424 2016-02-03T22:13:39+00:00 Doug Currie github.9.eeeeeee@spamgourmet.com 2016-01-31T03:35:58+00:00 urn:sha1:2e2e15cec2f85ece763f3f80152d759aecfad47c 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.