Class: Puma::ThreadPool

Inherits:
Object
  • Object
show all
Defined in:
lib/puma/thread_pool.rb

Overview

A simple thread pool management object.

Defined Under Namespace

Classes: AutoTrim

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(min, max, &blk) ⇒ ThreadPool

Maintain a minimum of min and maximum of max threads in the pool.

The block passed is the work that will be performed in each thread.



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# File 'lib/puma/thread_pool.rb', line 14

def initialize(min, max, &blk)
  @cond = ConditionVariable.new
  @mutex = Mutex.new

  @todo = []

  @spawned = 0
  @waiting = 0

  @min = min
  @max = max
  @block = blk

  @shutdown = false

  @trim_requested = 0

  @workers = []

  @auto_trim = nil

  @mutex.synchronize do
    min.times { spawn_thread }
  end
end

Instance Attribute Details

#spawned ⇒ Object (readonly)

Returns the value of attribute spawned.



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# File 'lib/puma/thread_pool.rb', line 40

def spawned
  @spawned
end

Instance Method Details

#<<(work) ⇒ Object

Add work to the todo list for a Thread to pickup and process.



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# File 'lib/puma/thread_pool.rb', line 109

def <<(work)
  @mutex.synchronize do
    if @shutdown
      raise "Unable to add work while shutting down"
    end

    @todo << work

    if @waiting == 0 and @spawned < @max
      spawn_thread
    end

    @cond.signal
  end
end

#auto_trim!(timeout = 5) ⇒ Object 



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# File 'lib/puma/thread_pool.rb', line 162

def auto_trim!(timeout=5)
  @auto_trim = AutoTrim.new(self, timeout)
  @auto_trim.start!
end

#backlog ⇒ Object

How many objects have yet to be processed by the pool?



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# File 'lib/puma/thread_pool.rb', line 44

def backlog
  @mutex.synchronize { @todo.size }
end

#shutdown ⇒ Object

Tell all threads in the pool to exit and wait for them to finish.



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# File 'lib/puma/thread_pool.rb', line 169

def shutdown
  @mutex.synchronize do
    @shutdown = true
    @cond.broadcast

    @auto_trim.stop if @auto_trim
  end

  # Use this instead of #each so that we don't stop in the middle
  # of each and see a mutated object mid #each
  @workers.first.join until @workers.empty?

  @spawned = 0
  @workers = []
end

#trim(force = false) ⇒ Object

If too many threads are in the pool, tell one to finish go ahead and exit. If force is true, then a trim request is requested even if all threads are being utilized.



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# File 'lib/puma/thread_pool.rb', line 129

def trim(force=false)
  @mutex.synchronize do
    if (force or @waiting > 0) and @spawned - @trim_requested > @min
      @trim_requested += 1
      @cond.signal
    end
  end
end