41 lines
1.3 KiB
Ruby
41 lines
1.3 KiB
Ruby
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# frozen_string_literal: true
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require 'fast_spec_helper'
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RSpec.describe Gitlab::Metrics::Memory do
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describe '.gc_heap_fragmentation' do
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subject(:call) do
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described_class.gc_heap_fragmentation(
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heap_live_slots: gc_stat_heap_live_slots,
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heap_eden_pages: gc_stat_heap_eden_pages
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)
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end
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context 'when the Ruby heap is perfectly utilized' do
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# All objects are located in a single heap page.
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let(:gc_stat_heap_live_slots) { described_class::HEAP_SLOTS_PER_PAGE }
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let(:gc_stat_heap_eden_pages) { 1 }
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it { is_expected.to eq(0) }
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end
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context 'when the Ruby heap is greatly fragmented' do
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# There is one object per heap page.
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let(:gc_stat_heap_live_slots) { described_class::HEAP_SLOTS_PER_PAGE }
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let(:gc_stat_heap_eden_pages) { described_class::HEAP_SLOTS_PER_PAGE }
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# The heap can never be "perfectly fragmented" because that would require
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# zero objects per page.
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it { is_expected.to be > 0.99 }
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end
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context 'when the Ruby heap is semi-fragmented' do
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# All objects are spread over two pages i.e. each page is 50% utilized.
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let(:gc_stat_heap_live_slots) { described_class::HEAP_SLOTS_PER_PAGE }
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let(:gc_stat_heap_eden_pages) { 2 }
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it { is_expected.to eq(0.5) }
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end
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end
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end
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