Feature #14329: Speedup `block.call` where `block` is passed block parameter.

• Status: Closed
• Assignee: ko1 (Koichi Sasada)
• Target version: 2.6

[ko1 (Koichi Sasada)]

abstract

Speedup block.call where block is passed block parameter with a special object named "proxyblock" which responds to call and invoke passed block.

background

Ruby 2.5 improved performance of passing a passed block parameter by lazy Proc creation ([Feature #14045]).
However, block.call (block is a passed block parameter) is not optimized and need to create a Proc object immediately.

proposal

We need to make Proc creation lazily for performance. There are several way to achieve it, but I propose to use special object named "blockproxy" object.

This is a pseudo code to use it:

# block is given block parameter

block.call(1, 2, 3)

#=> translate at compile time

if block is not modified and
   block is ISeq/IFunc block
  tmp = blockproxy
else
  tmp = block # create Proc and so on
end
tmp.call(1, 2, 3)

blockproxy.call invoke given block if Proc#call is not redefined, otherwise make a Proc and call Proc#call as usual.

Advantage of this method is we can also use this technique with the safe navigation operator (block&.call).
If block is not given, then tmp will be nil, and no method dispatched with &..

Note that this technique depends on the assumption "we can't access to the evaluated receiver just before method dispatch". We don't/can't access blockproxy object at method dispatch, and no compatibility issue.

evaluation

Using https://github.com/k0kubun/benchmark_driver

prelude: |
  def block_yield
    yield
  end
  def bp_yield &b
    yield
  end
  def bp_call &b
    b.call
  end
  def bp_safe_call &b
    b&.call
  end

benchmark:
  - block_yield{}
  - bp_yield{}
  - bp_call{}
  - bp_safe_call{}
  - bp_safe_call

Result:

Warming up --------------------------------------
       block_yield{}     1.298M i/100ms
          bp_yield{}     1.177M i/100ms
           bp_call{}   447.723k i/100ms
      bp_safe_call{}   413.261k i/100ms
        bp_safe_call     2.955M i/100ms
Calculating -------------------------------------
                          trunk    modified
       block_yield{}    20.672M     20.808M i/s -     51.933M in 2.512265s 2.495806s
          bp_yield{}    16.294M     16.220M i/s -     47.099M in 2.890459s 2.903797s
           bp_call{}     5.626M     14.752M i/s -     17.909M in 3.182966s 1.213976s # x2.62
      bp_safe_call{}     5.555M     14.557M i/s -     16.530M in 2.975892s 1.135586s # x2.62
        bp_safe_call    31.339M     23.561M i/s -    118.184M in 3.771157s 5.016200s

The patch is here:
https://gist.github.com/ko1/d8a1a9d92075b27a8e95ca528cc57fd2

[ko1 (Koichi Sasada)]

• Status changed from Open to Closed

move to ruby-core.