Re: [ANN] Ravi (a Lua 5.3 dialect) with LLVM JIT Compilation technology - Alpha Release 0.12

[Simon Cozens <simon@...>]

Hello! I just tried running SILE under Ravi.

There were a couple of problems setting it up:

Luarocks worked fine but it installed code into "/usr/local/lib/lua/
5.3" and "/usr/local/share/lua/ 5.3" (note the space).

Using "Ravi" as the LUA_VERSION name in lua.h is perfectly correct but
it breaks the AX_LUA_HEADERS autoconfig macro.

Otherwise, everything works, and all tests pass!

However, I am having problems with the JIT. Ravi typeset the SILE manual
in 13 seconds without JIT. Auto mode fails spectacularly - SILE takes up
huge amounts of RAM and there's no output. Turning on the JIT for
hot-spot functions doesn't seem to make a lot of difference; if anything
it makes it slower.

My guess is that the JIT makes sense for individual functions which run
for a long time, but for a collection of small functions which call each
other it doesn't seem to buy you very much at all. Maybe when you can
insert the code from one function into another we might see some speedup.