Is LuaJIT really faster than every other JIT-ed dynamic languages? [closed]

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According to the computer language benchmark game, the LuaJIT implementation seems to beat every other JIT-ed dynamic language (V8, Tracemonkey, PLT Scheme, Erlang HIPE) by an order of magnitude.

I know that these benchmarks are not representative (as they say: "Which programming language implementations have the fastest benchmark programs?"), but this is still really impressive.

In practice, is it really the case? Someone have tested that Lua implementation?

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There's a good discussion at Lambda the Ultimate. LuaJIT is very good.

Many people have reported impressive speedups on lua-l (the lua mailing list). The speedups are most impressive for pure Lua code; the trace compiler is not as effective when there are lots of calls to C functions in loadable library modules.

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In my case (a game prototype development), I observed no performance improvement at all. I use lua for embedding, so there are lots of calls to C++ library functions. Even though main loop is in a lua script and all of the important logic is implemented in lua, the overall performance was determined by rendering engines and physics engines implemented in C++. The original lua is already fast enough for such applications.

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I made an experiment with the lesson learned here: http://www.sampalib.org/luajit2.0_tunning.html Some data are not that valid anymore ( maxmcode=1024 is enough ), but luajit brings a robust improvement on a 600 lines of code pure Lua script (no C call to hit perfs...) that is not a large scale application nor an embedded use case but much more than the benchmarks.

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The performance of JIT depends on two things: performance of original scripting language, and the performance of the compiler.

Compiler is a pretty mature technique and most JIT compiler have comparable performance. However, lua itself, i.e. lua-without-JIT, is probably one of the fastest scripting language.

lua is faster than Java-without-JIT. lua is faster than Javascript-without-JIT. lua is faster than most-scripting-languages-without-JIT.

so,

lua-JIT is faster than Java-with-JIT (the sun Java), lua-JIT is faster than V8 (Javascript-with-JIT), etc, ...