Module: Git::Parallel

Defined in:
lib/git/parallel.rb

Overview

Minimal parallel helpers built on the Ruby standard library, replacing the former ‘pmap` gem. The work these drive is I/O-bound – every block shells out to git – so threads give real concurrency even under MRI’s GVL: a subprocess spawned by backticks runs outside the lock while other threads proceed. Keeping this in-tree is what lets git-report run on stock Ruby with no gems to install.

Constant Summary collapse

MAX_THREADS =

Upper bound on worker threads, and therefore on how many git subprocesses run at once. This cap is the whole point: a repository with thousands of authors must NOT spawn a thread (and a ‘git log`) per author – that would swamp the machine. 64 matches the historical default of the pmap gem this replaced, so throughput on large repositories is unchanged.

64

Class Method Summary collapse

Class Method Details

.peach(enum, &block) ⇒ Object

Like Enumerable#each, but runs the block for each element across a bounded pool of threads. Returns the original enumerable once all work is done.



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# File 'lib/git/parallel.rb', line 32

def peach(enum, &block)
  process(enum) { |item, _index| block.call(item) }
  enum
end

.pmap(enum, &block) ⇒ Object

Like Enumerable#map, but runs the block for each element across a bounded pool of threads and returns the results in the original order.



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# File 'lib/git/parallel.rb', line 20

def pmap(enum, &block)
  results = []
  mutex = Mutex.new
  process(enum) do |item, index|
    value = block.call(item)
    mutex.synchronize { results[index] = value }
  end
  results
end