67 lines
2.1 KiB
Ruby
67 lines
2.1 KiB
Ruby
# frozen_string_literal: true
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# This class uses a custom Ruby patch to allow
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# a per-thread memory allocation tracking in a efficient manner
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#
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# This concept is currently tried to be upstreamed here:
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# - https://github.com/ruby/ruby/pull/3978
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module Gitlab
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module Memory
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class Instrumentation
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KEY_MAPPING = {
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total_allocated_objects: :mem_objects,
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total_malloc_bytes: :mem_bytes,
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total_mallocs: :mem_mallocs
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}.freeze
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MUTEX = Mutex.new
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def self.available?
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Thread.respond_to?(:trace_memory_allocations=) &&
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Thread.current.respond_to?(:memory_allocations)
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end
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def self.start_thread_memory_allocations
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return unless available?
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MUTEX.synchronize do
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# This method changes a global state
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Thread.trace_memory_allocations = true
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end
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# it will return `nil` if disabled
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Thread.current.memory_allocations
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end
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# This method returns a hash with the following keys:
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# - mem_objects: number of allocated heap slots (as reflected by GC)
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# - mem_mallocs: number of malloc calls
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# - mem_bytes: number of bytes allocated by malloc for objects that did not fit
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# into a heap slot
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# - mem_total_bytes: number of bytes allocated for both objects consuming an object slot
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# and objects that required a malloc (mem_malloc_bytes)
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def self.measure_thread_memory_allocations(previous)
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return unless available?
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return unless previous
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current = Thread.current.memory_allocations
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return unless current
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# calculate difference in a memory allocations
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result = previous.to_h do |key, value|
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[KEY_MAPPING.fetch(key), current[key].to_i - value]
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end
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result[:mem_total_bytes] = result[:mem_bytes] + result[:mem_objects] * GC::INTERNAL_CONSTANTS[:RVALUE_SIZE]
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result
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end
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def self.with_memory_allocations
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previous = self.start_thread_memory_allocations
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yield
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self.measure_thread_memory_allocations(previous)
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end
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end
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end
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end
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