From: Caleb Clausen <vikkous@...>
Date: 2005-09-28T05:43:47+09:00
Subject: Re: Is there an issue with a library extending Object?

Some quick performance measurements:

class C
end

 class CC<C
 include Enumerable
 end

 Benchmark.measure {10000.times{ C.new}}
=> #<Benchmark::Tms:0x106f160 @total=0.0399999999999999, @cutime=0.0,
@label="", @stime=0.0, @real=0.104024171829224,
@utime=0.0399999999999999, @cstime=0.0>

 Benchmark.measure {10000.times{ CC.new}}
=> #<Benchmark::Tms:0x103af3c @total=0.04, @cutime=0.0, @label="",
@stime=0.0, @real=0.104261159896851, @utime=0.04, @cstime=0.0>

Benchmark.measure {10000.times{ C.new.extend Enumerable}}
=> #<Benchmark::Tms:0x104c5d4 @total=0.54, @cutime=0.0, @label="",
@stime=0.0, @real=0.683220148086548, @utime=0.54, @cstime=0.0>


So, it looks like better than 10x as expensive to instantiate and
extend as to just instantiate. (Some of my measurements showed more
like 20x.)

However, I wouldn't worry about the performance of extend unless you
have good reason to believe it's a bottleneck.