Module: Wurk::Swarm::Prefork

Defined in:
lib/wurk/swarm/prefork.rb

Overview

The parent's last memory step before its first fork, shared by every swarm entry point (wurkswarm and the railtie's co-hosted swarm): load what each child would otherwise load for itself (Wurk's autoloads included: Wurk.eager_load!), then settle the heap, so the children start on pages they share copy-on-write instead of N private copies. Opens no socket, so it may sit between steps 3 and 4. Its effect is the t=0 shared ratio in bench/rss_soak.rb (RSS_JOBS=0).

Constant Summary collapse

CHILD_FEATURES =

Features a child requires after the fork. fiddle arms PR_SET_PDEATHSIG (OrphanGuard#arm_pdeathsig) in every Linux child.

%w[fiddle].freeze

Class Method Summary collapse

Class Method Details

.require_child_features ⇒ Object 



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# File 'lib/wurk/swarm/prefork.rb', line 29

def require_child_features
  CHILD_FEATURES.each { |feature| try_require(feature) }
  # Only a host that loaded Vernier can profile a job (Profiler).
  try_require('tempfile') if defined?(::Vernier)
end

.run(env = ENV, periodic: nil) ⇒ Object

Once, before the first fork only: a respawn forks from a parent that may be a live web process, where a full compaction is a pause its requests would feel. RUBY_DISABLE_WARMUP=1 skips it, as it does Process.warmup.



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# File 'lib/wurk/swarm/prefork.rb', line 22

def run(env = ENV, periodic: nil)
  Wurk.eager_load!
  require_child_features
  Wurk::Cron.prefork(periodic) if periodic
  warmup unless env['RUBY_DISABLE_WARMUP'] == '1'
end

.try_require(feature) ⇒ Object 



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# File 'lib/wurk/swarm/prefork.rb', line 47

def try_require(feature)
  require feature
rescue ::LoadError
  nil
end

.warmup(process = ::Process, collector = ::GC) ⇒ Object

Process.warmup (Ruby >= 3.3) is a full GC, compaction, promotion of survivors to the old generation and a malloc_trim. The 3.2 floor gets the part it has: full GC, then compaction where the platform supports it.



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# File 'lib/wurk/swarm/prefork.rb', line 38

def warmup(process = ::Process, collector = ::GC)
  return process.warmup if process.respond_to?(:warmup)

  collector.start(full_mark: true, immediate_sweep: true)
  collector.compact if collector.respond_to?(:compact)
rescue ::NotImplementedError
  nil
end