guile/test-suite/tests/statprof.test

;; guile-lib                    -*- scheme -*-
;; Copyright (C) 2004, 2009, 2010, 2014 Andy Wingo <wingo at pobox dot com>
;; Copyright (C) 2001 Rob Browning <rlb at defaultvalue dot org>

;; This library is free software; you can redistribute it and/or
;; modify it under the terms of the GNU Lesser General Public
;; License as published by the Free Software Foundation; either
;; version 2.1 of the License, or (at your option) any later version.
;;
;; This library is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;; Lesser General Public License for more details.
;;
;; You should have received a copy of the GNU Lesser General Public
;; License along with this program; if not, contact:
;;
;; Free Software Foundation           Voice:  +1-617-542-5942
;; 59 Temple Place - Suite 330        Fax:    +1-617-542-2652
;; Boston, MA  02111-1307,  USA       gnu@gnu.org

;;; Commentary:
;;
;; Unit tests for (debugging statprof).
;;
;;; Code:

(define-module (test-suite test-statprof)
  #:use-module (test-suite lib)
  #:use-module (system base compile)
  #:use-module (srfi srfi-1)
  #:use-module (statprof))

;; Throw `unresolved' upon ENOSYS.  This is used to skip tests on
;; platforms such as GNU/Hurd where `ITIMER_PROF' is is currently
;; unimplemented.
(define-syntax-rule (when-implemented body ...)
  (catch 'system-error
    (lambda ()
      body ...)
    (lambda args
      (let ((errno (system-error-errno args)))
        (false-if-exception (statprof-stop))
        (if (= errno ENOSYS)
            (throw 'unresolved)
            (apply throw args))))))

(pass-if "statistical sample counts within expected range"
  (when-implemented
    ;; test to see that if we call 3 identical functions equally, they
    ;; show up equally in the call count, +/- 30%. it's a big range, and
    ;; I tried to do something more statistically valid, but failed (for
    ;; the moment).

    ;; make sure these are compiled so we're not swamped in `eval'
    (define (make-func)
      ;; Disable partial evaluation so that `(+ i i)' doesn't get
      ;; stripped.
      (compile '(lambda (n)
		  (do ((i 0 (+ i 1))) ((= 200 i)) (+ i i)))
	       #:opts '(#:partial-eval? #f)))
    (define run-test
      (compile '(lambda (num-calls funcs)
		  (let loop ((x num-calls) (funcs funcs))
		    (cond
		     ((positive? x)
		      ((car funcs) x)
		      (loop (- x 1) (cdr funcs))))))))

    (let ((num-calls 200000)
	  (funcs (circular-list (make-func) (make-func) (make-func))))

      ;; Run test. 20000 us == 200 Hz.
      (statprof-reset 0 20000 #f #f)
      (statprof-start)
      (run-test num-calls funcs)
      (statprof-stop)

      (let ((a-data (statprof-proc-call-data (car funcs)))
	    (b-data (statprof-proc-call-data (cadr funcs)))
	    (c-data (statprof-proc-call-data (caddr funcs))))
	(if (and a-data b-data c-data)
	    (let* ((samples (map statprof-call-data-cum-samples
				 (list a-data b-data c-data)))
		   (expected (/ (apply + samples) 3.0))
                   (diffs (map (lambda (x) (abs (- x expected)))
                               samples))
                   (max-diff (apply max diffs)))

	      (or (< max-diff (sqrt expected))
                  ;; don't stop the test suite for what statistically is
                  ;; bound to happen.
                  (begin
                    (format (current-warning-port)
                            ";;; warning: max diff ~a > (sqrt ~a)\n"
                            max-diff expected)
                    (throw 'unresolved))))

            ;; Samples were not collected for at least one of the
            ;; functions, possibly because NUM-CALLS is too low compared
            ;; to the CPU speed.
	    (throw 'unresolved (pk (list a-data b-data c-data))))))))

(pass-if "accurate call counting"
  (when-implemented
    ;; Test to see that if we call a function N times while the profiler
    ;; is active, it shows up N times.
    (let ((num-calls 200))

      (define do-nothing
        (compile '(lambda (n)
                    (simple-format #f "FOO ~A\n" (+ n n)))))
    
      ;; Run test.
      (statprof-reset 0 50000 #t #f)
      (statprof-start)
      (let loop ((x num-calls))
        (cond
         ((positive? x)
          (do-nothing x)
          (loop (- x 1))
          #t)))
      (statprof-stop)
    
      ;; Check result.
      (let ((proc-data (statprof-proc-call-data do-nothing)))
        (and proc-data
             (= (statprof-call-data-calls proc-data)
                num-calls))))))