diff options
| author | Paul Sokolovsky <pfalcon@users.sourceforge.net> | 2014-12-28 07:44:09 +0200 |
|---|---|---|
| committer | Damien George <damien.p.george@gmail.com> | 2014-12-29 00:07:47 +0000 |
| commit | 23f1b5ff66d94400ed629487d0893946cdf0a175 (patch) | |
| tree | 7852be2a2a95b95f01b3ffeb4531621c0994a4b9 /py | |
| parent | 96e22154d7fbdd4fe5a130ed8c009647d747b79d (diff) | |
| download | micropython-23f1b5ff66d94400ed629487d0893946cdf0a175.tar.gz micropython-23f1b5ff66d94400ed629487d0893946cdf0a175.zip | |
py: Add note about -fno-crossjumping when compiling vm.c.
Diffstat (limited to 'py')
| -rw-r--r-- | py/py.mk | 8 |
1 files changed, 8 insertions, 0 deletions
@@ -162,3 +162,11 @@ $(PY_BUILD)/gc.o: CFLAGS += $(CSUPEROPT) # optimising vm for speed, adds only a small amount to code size but makes a huge difference to speed (20% faster) $(PY_BUILD)/vm.o: CFLAGS += $(CSUPEROPT) +# Optimizing vm.o for modern deeply pipelined CPUs with branch predictors +# may require disabling tail jump optimization. This will make sure that +# each opcode has its own dispatching jump which will improve branch +# branch predictor efficiency. +# http://article.gmane.org/gmane.comp.lang.lua.general/75426 +# http://hg.python.org/cpython/file/b127046831e2/Python/ceval.c#l828 +# http://www.emulators.com/docs/nx25_nostradamus.htm +#-fno-crossjumping |