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- Subject: Re: Installing luaJIT : no performance gain !
- From: Sylvain Fabre <sylvain.fabre@...>
- Date: Tue, 25 Jan 2011 20:11:40 +0100
Thanks for you hints, Mike !
I finally found that the core reason is that we are using our internal
IDE to launch scripts during the development phase, and the IDE is using
the lua_debug interface, by settings some hooks.
When the script is called without this, it works perfectly !
Le 25/01/2011 16:16, Mike Pall a écrit :
Sylvain Fabre wrote:
After a few tests with some scripts, i have strictly no performance
gain between both versions. Even worse : in some cases, luaJIT is
slower than lua51.
How much of the CPU time of your application is spent in Lua code?
How much of the CPU time is spent in C/Lua and Lua/C transitions?
If you cannot readily answer these questions then I suggest to
profile your application first.
I am sure to use the right LUA DLL, as the "jit" object exists when
i link with luaJIT.
Umm, which version do you use?
I guess that i forgot something at the installation or run level. Any idea ?
Have you followed the instructions in
Or do you have a typical bench script, in order for me to be sure
that i can reproduce the same environnement than in the benchmark
page of luaJIT ?
Here's a trivial test:
local x=0; for i=1,1e9 do x=math.abs(x) end
This should run in a fraction of a second with LuaJIT 2.0, but
will take more than a minute with Lua. It's around 214x faster.
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