guix/profiling.scm

   1 ;;; GNU Guix --- Functional package management for GNU
   2 ;;; Copyright © 2017, 2019 Ludovic Courtès <ludo@gnu.org>
   3 ;;;
   4 ;;; This file is part of GNU Guix.
   5 ;;;
   6 ;;; GNU Guix is free software; you can redistribute it and/or modify it
   7 ;;; under the terms of the GNU General Public License as published by
   8 ;;; the Free Software Foundation; either version 3 of the License, or (at
   9 ;;; your option) any later version.
  10 ;;;
  11 ;;; GNU Guix is distributed in the hope that it will be useful, but
  12 ;;; WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ;;; GNU General Public License for more details.
  15 ;;;
  16 ;;; You should have received a copy of the GNU General Public License
  17 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 (define-module (guix profiling)
  20   #:use-module (ice-9 match)
  21   #:autoload   (ice-9 format) (format)
  22   #:export (profiled?
  23             register-profiling-hook!))
  24
  25 ;;; Commentary:
  26 ;;;
  27 ;;; Basic support for Guix-specific profiling.
  28 ;;;
  29 ;;; Code:
  30
  31 (define profiled?
  32   (let ((profiled
  33          (or (and=> (getenv "GUIX_PROFILING") string-tokenize)
  34              '())))
  35     (lambda (component)
  36       "Return true if COMPONENT profiling is active."
  37       (member component profiled))))
  38
  39 (define %profiling-hooks
  40   ;; List of profiling hooks.
  41   (map (match-lambda
  42          ("after-gc"       after-gc-hook)
  43          ((or "exit" #f)   exit-hook))
  44        (or (and=> (getenv "GUIX_PROFILING_EVENTS") string-tokenize)
  45            '("exit"))))
  46
  47 (define (register-profiling-hook! component thunk)
  48   "Register THUNK as a profiling hook for COMPONENT, a string such as
  49 \"rpc\"."
  50   (when (profiled? component)
  51     (for-each (lambda (hook)
  52                 (add-hook! hook thunk))
  53               %profiling-hooks)))
  54
  55 (define (show-gc-stats)
  56   "Display garbage collection statistics."
  57   (define MiB (* 1024 1024.))
  58   (define stats (gc-stats))
  59
  60   (format (current-error-port) "Garbage collection statistics:
  61   heap size:        ~,2f MiB
  62   allocated:        ~,2f MiB
  63   GC times:         ~a
  64   time spent in GC: ~,2f seconds (~d% of user time)~%"
  65           (/ (assq-ref stats 'heap-size) MiB)
  66           (/ (assq-ref stats 'heap-total-allocated) MiB)
  67           (assq-ref stats 'gc-times)
  68           (/ (assq-ref stats 'gc-time-taken)
  69              internal-time-units-per-second 1.)
  70           (inexact->exact
  71            (round (* (/ (assq-ref stats 'gc-time-taken)
  72                         (tms:utime (times)) 1.)
  73                      100)))))
  74
  75 (register-profiling-hook! "gc" show-gc-stats)