gnu: Add emacs-exec-path-from-shell.

[jackhill/guix/guix.git] / guix / profiling.scm

;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2017 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix 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 General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (guix profiling)
  #:use-module (ice-9 match)
  #:export (profiled?
            register-profiling-hook!))

;;; Commentary:
;;;
;;; Basic support for Guix-specific profiling.
;;;
;;; Code:

(define profiled?
  (let ((profiled
         (or (and=> (getenv "GUIX_PROFILING") string-tokenize)
             '())))
    (lambda (component)
      "Return true if COMPONENT profiling is active."
      (member component profiled))))

(define %profiling-hooks
  ;; List of profiling hooks.
  (map (match-lambda
         ("after-gc"       after-gc-hook)
         ((or "exit" #f)   exit-hook))
       (or (and=> (getenv "GUIX_PROFILING_EVENTS") string-tokenize)
           '("exit"))))

(define (register-profiling-hook! component thunk)
  "Register THUNK as a profiling hook for COMPONENT, a string such as
\"rpc\"."
  (when (profiled? component)
    (for-each (lambda (hook)
                (add-hook! hook thunk))
              %profiling-hooks)))