Class: RbBCC::PerfEventArray

Inherits:
TableBase show all
Includes:
EventTypeSupported
Defined in:
lib/rbbcc/table.rb

Instance Attribute Summary

Attributes inherited from TableBase

#bpf, #flags, #keysize, #keytype, #leafsize, #leaftype, #map_fd, #map_id, #name, #ttype

Instance Method Summary collapse

Methods included from EventTypeSupported

#get_event_class

Methods inherited from TableBase

#[], #[]=, #clear, #delete, #each_key, #each_pair, #each_value, #fetch, from_pin, #items, #next, #pin!, #print_linear_hist, #print_log2_hist, #structured_key?, #values

Methods included from CPUHelper

_read_cpu_range, get_online_cpus, get_possible_cpus

Constructor Details

#initialize(bpf, map_id, map_fd, keytype, leaftype, name: nil) ⇒ PerfEventArray

Returns a new instance of PerfEventArray.



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# File 'lib/rbbcc/table.rb', line 369

def initialize(bpf, map_id, map_fd, keytype, leaftype, name: nil)
  super
  @open_key_fds = {}
  @event_class = nil
  @_cbs = {}
  @_open_key_fds = {}
end

Instance Method Details

#_open_perf_buffer(cpu, callback, page_cnt, lost_cb) ⇒ Object 



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# File 'lib/rbbcc/table.rb', line 394

def _open_perf_buffer(cpu, callback, page_cnt, lost_cb)
  # bind("void raw_cb_callback(void *, void *, int)")
  fn = Fiddle::Closure::BlockCaller.new(
    Fiddle::TYPE_VOID,
    [Fiddle::TYPE_VOIDP, Fiddle::TYPE_VOIDP, Fiddle::TYPE_INT]
  ) do |_dummy, data, size|
    begin
      callback.call(cpu, data, size)
    rescue => e
      if Fiddle.last_error == 32 # EPIPE
        exit
      else
        raise e
      end
    end
  end
  lost_fn = Fiddle::Closure::BlockCaller.new(
    Fiddle::TYPE_VOID,
    [Fiddle::TYPE_VOIDP, Fiddle::TYPE_ULONG]
  ) do |_dummy, lost|
    begin
      lost_cb(lost)
    rescue => e
      if Fiddle.last_error == 32 # EPIPE
        exit
      else
        raise e
      end
    end
  end if lost_cb
  reader = Clib.bpf_open_perf_buffer(fn, lost_fn, nil, -1, cpu, page_cnt)
  if !reader || reader.null?
    raise "Could not open perf buffer"
  end
  fd = Clib.perf_reader_fd(reader)

  self[byref(cpu, @keysize)] = byref(fd, @leafsize)
  self.bpf.perf_buffers[[object_id, cpu]] = reader
  @_cbs[cpu] = [fn, lost_fn]
  @_open_key_fds[cpu] = -1
end

#event(data) ⇒ Object 



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# File 'lib/rbbcc/table.rb', line 377

def event(data)
  @event_class ||= (get_event_class || self.leaftype)
  ev = @event_class.malloc
  Fiddle::Pointer.new(ev.to_ptr)[0, @event_class.size] = data[0, @event_class.size]
  return ev
end

#open_perf_buffer(page_cnt: 8, lost_cb: nil, &callback) ⇒ Object 



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# File 'lib/rbbcc/table.rb', line 384

def open_perf_buffer(page_cnt: 8, lost_cb: nil, &callback)
  if page_cnt & (page_cnt - 1) != 0
    raise "Perf buffer page_cnt must be a power of two"
  end

  get_online_cpus.each do |i|
    _open_perf_buffer(i, callback, page_cnt, lost_cb)
  end
end