Module: HeapScope::Fragmentation

Defined in:
lib/heapscope/dominators.rb

Overview

Heuristic fragmentation / native mismatch indicators.

Class Method Summary collapse

Class Method Details

.assess(snapshot) ⇒ Object 



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# File 'lib/heapscope/dominators.rb', line 55

def assess(snapshot)
  gc = snapshot.gc_stat
  rss = snapshot.rss_bytes
  live = gc[:heap_live_slots]
  free = gc[:heap_free_slots]
  pages = gc[:heap_allocated_pages]
  return { status: :unknown, note: "Insufficient GC/RSS data." } if rss.nil? || live.nil?

  heap_bytes_estimate = live.to_i * 40 # very rough average slot estimate
  ratio = heap_bytes_estimate.positive? ? rss.to_f / heap_bytes_estimate : nil
  free_ratio = (live.to_i + free.to_i).positive? ? free.to_f / (live + free) : nil

  status =
    if ratio && ratio > 4.0 && pages.to_i > 100
      :potential_fragmentation
    elsif ratio && ratio > 2.5
      :elevated_rss_vs_heap
    else
      :normal
    end

  {
    status: status,
    rss_bytes: rss,
    heap_bytes_estimate: heap_bytes_estimate,
    rss_to_heap_ratio: ratio&.round(2),
    free_slot_ratio: free_ratio&.round(3),
    heap_allocated_pages: pages,
    note: "Potential allocator/heap fragmentation indicator — not confirmed fragmentation."
  }
end