Forum: Ruby Threads not concurrent

Hi my code looks like:
================few lines of codes
childredn=[]
for i in 1..2
  children[i-1]=Thread.new do
    DRb.start_service
    server_uri=ARGV.shift
    server = DRbObject.new nil, server_uri
    puts "A new thread created----------------------" #line alpha
    while !server.get_stop_flag
      sleep(i)
      puts "inside loop----------------------"
      begin
        obj=server.get_object_s
        if !(Obj===obj and obj!=nil)
          sleep(6)
          next
        end
        process=Process.new(obj)
        process.process_on()
        processed_obj=process.obj
        server.update_obj(processed_obj)
      rescue => e
        $logger.log_it("Error in client, ", e.message)
      end
    end
    puts "--A thread completed"
  end
end

children.each do |t|
  if t!=nil
    t.join
  end
end
================few lines of codes

#---------------
The sequence of print is like:
puts "A new thread created----------------------"
puts "A new thread created----------------------"
puts "inside loop----------------------"
--A thread completed
puts "inside loop----------------------"
--A thread completed

But I want:
puts "A new thread created----------------------"
puts "A new thread created----------------------"
puts "inside loop----------------------"
puts "inside loop----------------------"
--A thread completed
--A thread completed

For your information I have used 'system' to start this block of script
from another ruby script.

The blocked thread is blocked at #line alpha, i.e #line alpha is
executed, after that it stops (not killed but paused.)

Odd as it sounds, try printing to stderr and not stdout. Stdout is 
buffered and not reliable when trying to see thread output in real time.

That may not get your current issue, but it'll be a good start.

Hi, Ajay!

Your process of updating server i.e. the following code:

        process=Process.new(obj)
        process.process_on()
        processed_obj=process.obj
        server.update_obj(processed_obj)

is taking different times to complete in the two threads. Hopefully, you
can fix this by trying to tweak the {{ sleep(6) }}. For example the
following code (of course in your version) may fix your problem:

#!/usr/bin/env ruby
children=[]
for i in 1..2
  children[i-1]=Thread.new do
    stop_flag = false
    puts "A new thread created----------------------" #line alpha
    while !stop_flag
      sleep(i)
      puts "inside loop----------------------"

      sleep(i==2?6:1)  # <<< This will fix your problem
      stop_flag = true
      next
    end
    puts "--A thread completed"
  end
  sleep 0.5  # <<< Try delaying creation of threads for short time
end
children.each { |t| t.join }


Regards, igor