Class: HeapScope::Aging

Inherits:
Object
  • Object
show all
Defined in:
lib/heapscope/aging.rb

Overview

Approximate object aging across forced GC cycles. Does not invent ages the runtime cannot support — labels are coarse.

Defined Under Namespace

Classes: Sample

Constant Summary collapse

BUCKETS = 
%i[young middle_aged long_lived unknown].freeze

Instance Method Summary collapse

Constructor Details

#initialize(runtime: Runtime.current) ⇒ Aging

Returns a new instance of Aging.



11
12
13
14
 
# File 'lib/heapscope/aging.rb', line 11

def initialize(runtime: Runtime.current)
  @runtime = runtime
  @samples = []
end

Instance Method Details

#classify(class_name) ⇒ Object 



38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
 
# File 'lib/heapscope/aging.rb', line 38

def classify(class_name)
  series = @samples.map { |s| s.class_counts[class_name].to_i }
  return { bucket: :unknown, series: series } if series.size < 2

  first = series.first
  last = series.last
  survived_ratio = first.positive? ? last.to_f / first : 0.0
  bucket =
    if survived_ratio < 0.2
      :young
    elsif survived_ratio < 0.7
      :middle_aged
    else
      :long_lived
    end

  {
    class: class_name,
    bucket: bucket,
    series: series,
    survived_ratio: survived_ratio.round(4),
    note: "Coarse age bucket from multi-cycle survival — not exact object age."
  }
end

#push_counts(cycle:, counts:, generation_hint: nil) ⇒ Object 



33
34
35
36
 
# File 'lib/heapscope/aging.rb', line 33

def push_counts(cycle:, counts:, generation_hint: nil)
  @samples << Sample.new(cycle_index: cycle, class_counts: counts, generation_hint: generation_hint)
  self
end

#report(top: 20) ⇒ Object 



63
64
65
66
67
68
69
 
# File 'lib/heapscope/aging.rb', line 63

def report(top: 20)
  names = @samples.flat_map { |s| s.class_counts.keys }.uniq
  names.map { |n| classify(n) }
       .select { |r| r[:series].last.to_i > 10 }
       .sort_by { |r| -r[:survived_ratio] }
       .first(top)
end

#sample!(cycle:) ⇒ Object 



16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
 
# File 'lib/heapscope/aging.rb', line 16

def sample!(cycle:)
  counts = Hash.new(0)
  if @runtime.each_object?
    @runtime.each_object do |obj|
      name = begin
        obj.class.name
      rescue StandardError
        nil
      end
      next unless name

      counts[name] += 1
    end
  end
  push_counts(cycle: cycle, counts: counts, generation_hint: (GC.stat[:count] if GC.respond_to?(:stat)))
end