Re: Luajit string concatenation performance
- From: Szabó Antal <szabo.antal.92@xxxxxxxxx>
- To: luajit@xxxxxxxxxxxxx
- Date: Wed, 22 May 2013 22:38:51 +0200
I ran this test too out of curiosity, and here are my results:
(I replaced os.time() with os.clock())
Lua 5.1: 10.769 seconds
Lua 5.2: 10.99 seconds
LuaJIT 2.0.1: 8.781 seconds
LuaJIT 2.1.0-alpha: 21.346 seconds
where both LuaJITs are the latest git version.
So in my case, LuaJIT 2.0.1 is the fastest.
2013/5/22 Geoff Leyland <geoff_leyland@xxxxxxxxxxx>:
> On 23/05/2013, at 7:43 AM, madigest i <madigest@xxxxxxxxxxxxx> wrote:
>
>> Hello.
>>
>> I have had strange performance problems with many of my different Lua
>> programs that handle big strings. I finally made a small test program to
>> demonstrate the problem.
>>
>> Here are the results in OSX:
>> LuaJIT 2.1.0-alpha: 46 seconds
>> LuaJIT 2.0.1: 39 seconds
>> Lua 5.1: 22 seconds
>
> LuaJIT 2 doesn't compile string concatenation, and LuaJIT 2.1 doesn't compile
> the gmatch.
>
> I realise this is a test case, not your real code, but why isn't your inner
> loop like:
>
> local codeout = {}
> local timeUsed = os.time()
> for line in code:gmatch("[^\r\n]+") do
> codeout[#codeout+1] = line.."\n"
> end
> codeout = table.concat(codeout, "")
> timeUsed = os.time() - timeUsed
>
> That takes 0s on all versions. (Use os.clock in preference to os.time, it
> has better resolution)
>
>
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