discourse/lib/method_profiler.rb

50 lines
1.5 KiB
Ruby

# see https://samsaffron.com/archive/2017/10/18/fastest-way-to-profile-a-method-in-ruby
class MethodProfiler
def self.patch(klass, methods, name)
patches = methods.map do |method_name|
<<~RUBY
unless defined?(#{method_name}__mp_unpatched)
alias_method :#{method_name}__mp_unpatched, :#{method_name}
def #{method_name}(*args, &blk)
unless prof = Thread.current[:_method_profiler]
return #{method_name}__mp_unpatched(*args, &blk)
end
begin
start = Process.clock_gettime(Process::CLOCK_MONOTONIC)
#{method_name}__mp_unpatched(*args, &blk)
ensure
data = (prof[:#{name}] ||= {duration: 0.0, calls: 0})
data[:duration] += Process.clock_gettime(Process::CLOCK_MONOTONIC) - start
data[:calls] += 1
end
end
end
RUBY
end.join("\n")
klass.class_eval patches
end
def self.transfer
result = Thread.current[:_method_profiler]
Thread.current[:_method_profiler] = nil
result
end
def self.start(transfer = nil)
Thread.current[:_method_profiler] = transfer || {
__start: Process.clock_gettime(Process::CLOCK_MONOTONIC)
}
end
def self.stop
finish = Process.clock_gettime(Process::CLOCK_MONOTONIC)
if data = Thread.current[:_method_profiler]
Thread.current[:_method_profiler] = nil
start = data.delete(:__start)
data[:total_duration] = finish - start
end
data
end
end