circuitpython/docs
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
..
develop docs: Replace ufoo with foo in all docs. 2021-08-13 22:53:29 +10:00
differences docs/differences: Clarify the differences are against Python 3.4. 2019-01-11 12:11:02 +11:00
esp32 docs: Replace ufoo with foo in all docs. 2021-08-13 22:53:29 +10:00
esp8266 docs/esp8266: Use monospace for software tools. 2021-08-30 23:51:27 +10:00
library docs/library/machine.I2S.rst: Specify that I2S.shift args are kw-only. 2021-09-13 18:21:46 +10:00
pyboard stm32: Suggest putting code in main.py not boot.py. 2021-09-16 12:40:05 +10:00
readthedocs/settings docs: Add RTD local_settings file, to add custom templates. 2014-12-21 11:21:06 +00:00
reference all: Remove MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE. 2021-09-16 16:04:03 +10:00
rp2 docs: Replace ufoo with foo in all docs. 2021-08-13 22:53:29 +10:00
static docs: Add M-logo as favicon. 2017-02-07 20:04:40 +11:00
templates docs/templates: Add unix and zephyr quickref links to top-index. 2021-08-13 20:21:21 +10:00
unix windows: Improve default search path. 2020-02-11 13:34:35 +11:00
wipy docs: Replace ufoo with foo in all docs. 2021-08-13 22:53:29 +10:00
zephyr docs: Replace ufoo with foo in all docs. 2021-08-13 22:53:29 +10:00
conf.py all: Bump version to 1.17. 2021-09-02 00:07:13 +10:00
index.rst docs/zephyr: Add quick reference for the Zephyr port. 2021-08-13 20:20:57 +10:00
license.rst docs/license: Update copyright year. 2017-06-23 21:48:27 +03:00
make.bat docs/make.bat: Change Windows output dir from '_build' to 'build'. 2021-09-13 18:15:38 +10:00
Makefile docs: Fix Sphinx 3.x warnings, and enable warnings-as-errors on build. 2020-06-05 21:42:17 +10:00
README.md docs/README: Add short paragraph about using readthedocs. 2020-01-12 11:45:55 +11:00

MicroPython Documentation

The MicroPython documentation can be found at: http://docs.micropython.org/en/latest/

The documentation you see there is generated from the files in the docs tree: https://github.com/micropython/micropython/tree/master/docs

Building the documentation locally

If you're making changes to the documentation, you may want to build the documentation locally so that you can preview your changes.

Install Sphinx, and optionally (for the RTD-styling), sphinx_rtd_theme, preferably in a virtualenv:

 pip install sphinx
 pip install sphinx_rtd_theme

In micropython/docs, build the docs:

make html

You'll find the index page at micropython/docs/build/html/index.html.

Having readthedocs.org build the documentation

If you would like to have docs for forks/branches hosted on GitHub, GitLab or BitBucket an alternative to building the docs locally is to sign up for a free https://readthedocs.org account. The rough steps to follow are:

  1. sign-up for an account, unless you already have one
  2. in your account settings: add GitHub as a connected service (assuming you have forked this repo on github)
  3. in your account projects: import your forked/cloned micropython repository into readthedocs
  4. in the project's versions: add the branches you are developing on or for which you'd like readthedocs to auto-generate docs whenever you push a change

PDF manual generation

This can be achieved with:

make latexpdf

but require rather complete install of LaTeX with various extensions. On Debian/Ubuntu, try (500MB+ download):

apt-get install texlive-latex-recommended texlive-latex-extra