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gc_jemalloc_tuning

⚙️ Tune Ruby GC with jemalloc and GC::Profiler​

Reduce GC pauses by switching to jemalloc (or tcmalloc) and fine‐tuning Ruby's GC parameters. Combine this with GC::Profiler to spot allocation hotspots and adjust the heap slots dynamically.

# Use jemalloc in production
export LD_PRELOAD="/usr/lib/x86_64-linux-gnu/libjemalloc.so"

# In config/puma.rb
on_worker_boot do
  GC::Profiler.enable
  GC::OPTS[:min_heap_slots] = 200_000
  GC::OPTS[:heap_growth_factor] = 1.2
end
# At runtime, print GC stats for your slow actions
ActiveSupport::Notifications.subscribe('process_action.action_controller') do |*args|
  event = ActiveSupport::Notifications::Event.new(*args)
  puts "GC time: "+GC::Profiler.result
end

Iterate on :min_heap_slots and :heap_growth_factor until you see fewer GC invocations under high load.