Class: MemoryProfiler::Reporter

Inherits:
Object
  • Object
show all
Defined in:
lib/memory_profiler/reporter.rb

Overview

Reporter is the top level API used for generating memory reports.

Examples:

Measure object allocation in a block

report = Reporter.report(top: 50) do
  5.times { "foo" }
end

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts = {}) ⇒ Reporter

Returns a new instance of Reporter.



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# File 'lib/memory_profiler/reporter.rb', line 12

def initialize(opts = {})
  @top          = opts[:top] || 50
  @trace        = opts[:trace] && Array(opts[:trace])
  @ignore_files = opts[:ignore_files] && Regexp.new(opts[:ignore_files])
  @allow_files  = opts[:allow_files] && /#{Array(opts[:allow_files]).join('|')}/
end

Instance Attribute Details

#top ⇒ Object (readonly)

Returns the value of attribute top.



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# File 'lib/memory_profiler/reporter.rb', line 10

def top
  @top
end

#trace ⇒ Object (readonly)

Returns the value of attribute trace.



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# File 'lib/memory_profiler/reporter.rb', line 10

def trace
  @trace
end

Class Method Details

.report(opts = {}, &block) ⇒ MemoryProfiler::Results

Helper for generating new reporter and running against block.

Parameters:

  • opts (Hash) (defaults to: {}) —

    the options to create a report with

Options Hash (opts):

  • :top (Object) —

    max number of entries to output

  • :trace (Object) —

    a class or an array of classes you explicitly want to trace

  • :ignore_files (Object) —

    a regular expression used to exclude certain files from tracing

  • :allow_files (Object) —

    a string or array of strings to selectively include in tracing

Returns:



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# File 'lib/memory_profiler/reporter.rb', line 26

def self.report(opts={}, &block)
  self.new(opts).run(&block)
end

Instance Method Details

#run(&block) ⇒ Object

Collects object allocation and memory of ruby code inside of passed block.



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# File 'lib/memory_profiler/reporter.rb', line 31

def run(&block)

  GC.start
  GC.disable

  generation = GC.count
  ObjectSpace.trace_object_allocations do
    block.call
  end
  allocated = object_list(generation)
  retained = StatHash.new.compare_by_identity

  GC.enable
  GC.start

  # Caution: Do not allocate any new Objects between the call to GC.start and the completion of the retained
  #          lookups. It is likely that a new Object would reuse an object_id from a GC'd object.

  ObjectSpace.each_object do |obj|
    next unless ObjectSpace.allocation_generation(obj) == generation
    begin
      found = allocated[obj.__id__]
      retained[obj.__id__] = found if found
    rescue
      # __id__ is not defined on BasicObject, skip it
      # we can probably transplant the object_id at this point,
      # but it is quite rare
    end
  end
  ObjectSpace.trace_object_allocations_clear

  results = Results.new
  results.register_results(allocated, retained, top)
  results
end