From: "M. Edward (Ed) Borasky" <znmeb@...>
Date: 2007-10-28T04:31:15+09:00
Subject: Re: How fast does your Ruby run?

Lionel Bouton wrote:
> Daniel Sch�mer wrote:
>> Gentoo Linux on Intel Pentium 4 2.40GHz (512 KB cache):
>>
>> Ruby  Patch Platform            Seconds   Iterations per second
>> ===== ===== =================== ========= =====================
>> 1.8.6   111 i686-linux (gentoo) 32.801483  30486
>> 1.8.6  5000 i686-linux          13.607635  73488
>> 1.9.0     0 i686-linux           3.988949 250692
>> 1.8.5  3876 java                63.589     15725
>> 1.8.5  3876 java (-J-server)    44.173     22638
>> 1.8.5  3876 java (-O)           36.917     27087
>> 1.8.5  3876 java (-O -J-server) 15.194     65815
>>
>> The first is the system installed ruby.
> 
> IIRC on my Gentoo I got +80% on this particular benchmark with
> USE="-threads". Given this huge difference I looked at the speedup for
> the test suite of one of my Rails applications and got only ~ +10%.
> 
> That said I use Xpath in one Ruby script and the speedup was
> unbelievable : maybe +1000% (yes 3 zeros, the script took more than a
> minute, maybe several and with USE="-threads" it went through the data
> in less than ten seconds).
> I believe Ruby compiled with pthread is known to have performance
> problems (at least on Linux as I've seen reports of such behavior on
> Linux before)...
> 
> If you want speed on Linux (and maybe other flavours of Unix), you
> should look at compiling it without pthread. Warning: as some classes
> may use system libs that *are* compiled with pthread, you might not have
> this choice (IIRC the pthread support is there just to support such
> libraries).
> 
> If someone knows more about this subject (and how to tell if compiling
> without pthread is safe), I'd love to know the details.
> 
> Regards,
> 
> Lionel
> 
> 

Well, on Gentoo you'd need to turn off the "threads" USE flag globally. 
Either everything (in this case Ruby and Tcl/Tk for sure) is with 
"threads" or everything is without it. Personally, on my two UP systems 
(non-SMP) I turn it off and on my dual-core SMP system I turn it on. But 
that's really superstition more than anything based on measurements.

I can't speak for other distros, Windows, Intel vs. AMD, etc. But as far 
as I know on Gentoo it's safe to go "-threads" across the board even on 
an SMP system. I'm going to go ahead and turn it off on the dual-core 
and see what happens -- I'm wrapping up some benchmarking tests this 
weekend so it's a good time to play around with it in a controlled 
environment.