From: Christian Pedaschus <chris@...4-u.net>
Date: 2011-10-22T01:25:05+09:00
Subject: Re: Creating threads can be slow?

On 10/21/2011 05:49 PM, Robert Klemme wrote:
> On Fri, Oct 21, 2011 at 5:41 PM, wam r. <wamrewam@googlemail.com> wrote:
>> I am currently load testing a system. Under load, the couple of lines
>> below where I am creating threads are becoming slow:
> Well, under load anything is slow, isn't it? :-)
>
>> temp = []
>> foo_array.each do |foo|
>>  temp << Thread.new (foo) { |e| ...}
>> end
> Btw, you can simplify that to
>
> temp = foo_array.map {|foo| Thread.new(foo) {|e| ...}}
>
>> I have put a "timer" around these few lines. I know it is completely
>> dependent on the system but just to give an idea it can take more than
>> 20s for <> 100 threads. Just the code above. I am using 1.8.7 and the
>> standard MRI.
>>
>> Am I missing something? Do threads involve a significant overhead?
> Generally, i.e. in many common programming languages, creating threads
> is quite an expensive operation (compared to a method call for
> example) because of the overhead involved (allocating the stack and
> other things which need to be done).  Having said that you might want
> to try 1.9* versions of Ruby which are generally faster than 1.8*.
>
> Kind regards
>
> robert
>
And just in case Ruby 1.9* is not an option, you may want to try Ruby
Enterprise Edition which "could" be faster than MRI (untested guess, but
i had cases where it produced significant speedups so it may be worth a
try).

http://www.rubyenterpriseedition.com/

Greets, Chris