Historia

Jim Mussared b326edf68c all: Remove MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE. This commit removes all parts of code associated with the existing MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE optimisation option, including the -mcache-lookup-bc option to mpy-cross. This feature originally provided a significant performance boost for Unix, but wasn't able to be enabled for MCU targets (due to frozen bytecode), and added significant extra complexity to generating and distributing .mpy files. The equivalent performance gain is now provided by the combination of MICROPY_OPT_LOAD_ATTR_FAST_PATH and MICROPY_OPT_MAP_LOOKUP_CACHE (which has been enabled on the unix port in the previous commit). It's hard to provide precise performance numbers, but tests have been run on a wide variety of architectures (x86-64, ARM Cortex, Aarch64, RISC-V, xtensa) and they all generally agree on the qualitative improvements seen by the combination of MICROPY_OPT_LOAD_ATTR_FAST_PATH and MICROPY_OPT_MAP_LOOKUP_CACHE. For example, on a "quiet" Linux x64 environment (i3-5010U @ 2.10GHz) the change from CACHE_MAP_LOOKUP_IN_BYTECODE, to LOAD_ATTR_FAST_PATH combined with MAP_LOOKUP_CACHE is: diff of scores (higher is better) N=2000 M=2000 bccache -> attrmapcache diff diff% (error%) bm_chaos.py 13742.56 -> 13905.67 : +163.11 = +1.187% (+/-3.75%) bm_fannkuch.py 60.13 -> 61.34 : +1.21 = +2.012% (+/-2.11%) bm_fft.py 113083.20 -> 114793.68 : +1710.48 = +1.513% (+/-1.57%) bm_float.py 256552.80 -> 243908.29 : -12644.51 = -4.929% (+/-1.90%) bm_hexiom.py 521.93 -> 625.41 : +103.48 = +19.826% (+/-0.40%) bm_nqueens.py 197544.25 -> 217713.12 : +20168.87 = +10.210% (+/-3.01%) bm_pidigits.py 8072.98 -> 8198.75 : +125.77 = +1.558% (+/-3.22%) misc_aes.py 17283.45 -> 16480.52 : -802.93 = -4.646% (+/-0.82%) misc_mandel.py 99083.99 -> 128939.84 : +29855.85 = +30.132% (+/-5.88%) misc_pystone.py 83860.10 -> 82592.56 : -1267.54 = -1.511% (+/-2.27%) misc_raytrace.py 21490.40 -> 22227.23 : +736.83 = +3.429% (+/-1.88%) This shows that the new optimisations are at least as good as the existing inline-bytecode-caching, and are sometimes much better (because the new ones apply caching to a wider variety of map lookups). The new optimisations can also benefit code generated by the native emitter, because they apply to the runtime rather than the generated code. The improvement for the native emitter when LOAD_ATTR_FAST_PATH and MAP_LOOKUP_CACHE are enabled is (same Linux environment as above): diff of scores (higher is better) N=2000 M=2000 native -> nat-attrmapcache diff diff% (error%) bm_chaos.py 14130.62 -> 15464.68 : +1334.06 = +9.441% (+/-7.11%) bm_fannkuch.py 74.96 -> 76.16 : +1.20 = +1.601% (+/-1.80%) bm_fft.py 166682.99 -> 168221.86 : +1538.87 = +0.923% (+/-4.20%) bm_float.py 233415.23 -> 265524.90 : +32109.67 = +13.756% (+/-2.57%) bm_hexiom.py 628.59 -> 734.17 : +105.58 = +16.796% (+/-1.39%) bm_nqueens.py 225418.44 -> 232926.45 : +7508.01 = +3.331% (+/-3.10%) bm_pidigits.py 6322.00 -> 6379.52 : +57.52 = +0.910% (+/-5.62%) misc_aes.py 20670.10 -> 27223.18 : +6553.08 = +31.703% (+/-1.56%) misc_mandel.py 138221.11 -> 152014.01 : +13792.90 = +9.979% (+/-2.46%) misc_pystone.py 85032.14 -> 105681.44 : +20649.30 = +24.284% (+/-2.25%) misc_raytrace.py 19800.01 -> 23350.73 : +3550.72 = +17.933% (+/-2.79%) In summary, compared to MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE, the new MICROPY_OPT_LOAD_ATTR_FAST_PATH and MICROPY_OPT_MAP_LOOKUP_CACHE options: - are simpler; - take less code size; - are faster (generally); - work with code generated by the native emitter; - can be used on embedded targets with a small and constant RAM overhead; - allow the same .mpy bytecode to run on all targets. See #7680 for further discussion. And see also #7653 for a discussion about simplifying mpy-cross options. Signed-off-by: Jim Mussared <jim.mussared@gmail.com>		2021-09-16 16:04:03 +10:00
..
.gitignore	mpy-cross: Add new component, a cross compiler for MicroPython bytecode.	2016-02-25 10:12:21 +00:00
Makefile	all: Update to point to files in new shared/ directory.	2021-07-12 17:08:10 +10:00
README.md	all: Remove MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE.	2021-09-16 16:04:03 +10:00
gccollect.c	all: Update to point to files in new shared/ directory.	2021-07-12 17:08:10 +10:00
main.c	all: Remove MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE.	2021-09-16 16:04:03 +10:00
mpconfigport.h	all: Remove MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE.	2021-09-16 16:04:03 +10:00
mphalport.h	mpy-cross: Make build independent of extmod directory.	2018-07-10 14:11:28 +10:00
mpy-cross.vcxproj	all: Update to point to files in new shared/ directory.	2021-07-12 17:08:10 +10:00
qstrdefsport.h	mpy-cross: Add new component, a cross compiler for MicroPython bytecode.	2016-02-25 10:12:21 +00:00

README.md

MicroPython cross compiler

This directory contains the MicroPython cross compiler, which runs under any Unix-like system and compiles .py scripts into .mpy files.

Build it as usual:

$ make

The compiler is called mpy-cross. Invoke it as:

$ ./mpy-cross foo.py

This will create a file foo.mpy which can then be copied to a place accessible by the target MicroPython runtime (eg onto a pyboard's filesystem), and then imported like any other Python module using import foo.

Different target runtimes may require a different format of the compiled bytecode, and such options can be passed to the cross compiler.

If the Python code contains @native or @viper annotations, then you must specify -march to match the target architecture.

Run ./mpy-cross -h to get a full list of options.

The optimisation level is 0 by default. Optimisation levels are detailed in https://docs.micropython.org/en/latest/library/micropython.html#micropython.opt_level