From: Joel VanderWerf <vjoel@...>
Date: 2007-10-17T15:28:33+09:00
Subject: Re: Struct is slow

Sylvain Joyeux wrote:
>> I'm not sure whether you are familiar with Benchmark#bmbm which does a
>> rehearsal - personally I rather not switch off GC since in realistic
>> situations GC time belongs into the mix.  But results are rather
>> similar:
> Sure. GC does belong to the mix. Now, if GC is enabled you are not able to 
> compare anything. Let's assume that GC runs during 'array init', you will 
> say 'hey, struct init is faster'. Now, if GC runs during 'struct init' the 
> result may change ...
> 
> Keeping GC is meaningful when benchmarking a whole application. In 
> microbenchmarks like these, it is simply noise.

For fairness, you could do it this way (assuming REP is large enough):

...
Benchmark.bmbm 15 do |x|
   GC.start
   x.report 'struct init' do
     REP.times { Foo.new data, data }
     GC.start
   end

   GC.start
   x.report 'array init' do
     REP.times { [data, data] }
     GC.start
   end
...

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407