Module: GC

Defined in:
lib/jruby/gc_stats.rb

Constant Summary collapse

GC_MBEANS = 
ManagementFactory.garbage_collector_mxbeans
POOL_MBEANS = 
ManagementFactory.memory_pool_mxbeans

Class Method Summary collapse

Class Method Details

.allocation_size ⇒ Object

A delta in the committed (active main memory) size of all memory pools



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# File 'lib/jruby/gc_stats.rb', line 62

def self.allocation_size
  new_size = _total_pool_size
  new_size - @start_size
end

.collections ⇒ Object

Number of GC runs since stat collection started. This is accumulated across all GCs in the system.



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# File 'lib/jruby/gc_stats.rb', line 23

def self.collections
  raise "GC stats are not enabled" unless @enabled
  new_count = _collection_count
  new_count - @start_count
end

.disable_stats ⇒ Object 



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# File 'lib/jruby/gc_stats.rb', line 17

def self.disable_stats
  @enabled = false
end

.dump ⇒ Object

Dumping the basic data for each pool



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# File 'lib/jruby/gc_stats.rb', line 44

def self.dump
  filename = ENV['RUBY_GC_DATA_FILE']
  begin
    file = filename ? File.open(filename, 'w') : $stderr
    for pool_bean in POOL_MBEANS
      file.puts "Name: #{pool_bean.name}"
      file.puts "  Type: #{pool_bean.type}"
      file.puts "  Peak usage: #{pool_bean.peak_usage}"
      file.puts "  Current usage: #{pool_bean.usage}"
      file.puts "  Usage after last collection: #{pool_bean.collection_usage}"
      file.puts "  Managers: #{pool_bean.memory_manager_names.to_a.join(', ')}"
    end
  ensure
    file.close if filename
  end
end

.enable_stats ⇒ Object

no perf penalty for stats on JVM, but save current counts



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# File 'lib/jruby/gc_stats.rb', line 11

def self.enable_stats
  @enabled = true
  @start_count = _collection_count
  @start_time = _collection_time
  @start_size = _total_pool_size
end

.growth ⇒ Object

Number of heap bytes requested since the last GC run. This includes all memory pools.



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# File 'lib/jruby/gc_stats.rb', line 39

def self.growth
  _usage_versus_collected
end

.num_allocations ⇒ Object 



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# File 'lib/jruby/gc_stats.rb', line 67

def self.num_allocations
  # not sure this can be tracked on JVM; allocations happen all over
end

.time ⇒ Object

Amount of time spent in GC since stat collection started This is accumulated across all GCs in the system.



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# File 'lib/jruby/gc_stats.rb', line 31

def self.time
  raise "GC stats are not enabled" unless @enabled
  new_time = _collection_time
  new_time - @start_time
end