From: Robert Klemme <shortcutter@...>
Date: 2012-08-29T02:31:28+09:00
Subject: Re: force child threads run paralelly?

On Tue, Aug 28, 2012 at 6:11 PM, Andriy Andreyev <andreev00@gmail.com> wrote:
> Sorry for jumping in, but Tony, can you please explain what the idea is
> behind having Threads implemented and not allowing them to be executed in
> parallel? Thanks in advance.

You can still get enough concurrent execution for a large class of
applications that way.  This is true namely for applications which do
a lot IO.  You can try it out yourself:

$ ruby19 -e '5.times.map {|t| Thread.new(t) {|id| 10.times {|i| printf
"th-%p: %5d\n",id,i}}}.each(&:join)'
th-0:     0
th-0:     1
th-1:     0
th-2:     0
th-0:     2
th-3:     0
th-0:     3
th-2:     1
th-4:     0
th-1:     1
th-2:     2
th-0:     4
th-3:     1
th-4:     1
th-2:     3
th-1:     2
th-3:     2
th-0:     5
th-4:     2
th-3:     3
th-1:     3
th-2:     4
th-4:     3
th-0:     6
th-3:     4
th-2:     5
th-1:     4
th-0:     7
th-4:     4
th-3:     5
th-1:     5
th-2:     6
th-0:     8
th-3:     6
th-4:     5
th-1:     6
th-0:     9
th-2:     7
th-3:     7
th-1:     7
th-4:     6
th-2:     8
th-1:     8
th-3:     8
th-2:     9
th-4:     7
th-1:     9
th-3:     9
th-4:     8
th-4:     9

Also, this approach allows to have multithreading on a platform which
does not support threads out of the box.  Granted, these are rare
nowadays - that was more important in the early days.

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
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