benchmark.el

;; Benchmarking copied from Steve Purcell: https://github.com/purcell/emacs.d
;;
;; Stores the load times into the mk/required-times variable.

(defun mk/time-subtract-millis (b a)
  (* 1000.0 (float-time (time-subtract b a))))

(defvar mk/require-times nil
  "A list of (FEATURE . LOAD-DURATION).
LOAD-DURATION is the time taken in milliseconds to load FEATURE.")

(defadvice require
  (around build-require-times (feature &optional filename noerror) activate)
  "Note in `mk/require-times' the time taken to require each feature."
  (let* ((already-loaded (memq feature features))
         (require-start-time (and (not already-loaded) (current-time))))
    (prog1
        ad-do-it
      (when (and (not already-loaded) (memq feature features))
        (add-to-list 'mk/require-times
                     (cons feature
                           (mk/time-subtract-millis (current-time)
                                                           require-start-time))
                     t)))))