lib-src/profile.c

   1 /* profile.c --- generate periodic events for profiling of Emacs Lisp code.
   2    Copyright (C) 1992, 1994, 1999, 2001-2018 Free Software Foundation,
   3    Inc.
   4
   5 Author: Boaz Ben-Zvi <boaz@lcs.mit.edu>
   6
   7 This file is part of GNU Emacs.
   8
   9 GNU Emacs is free software: you can redistribute it and/or modify
  10 it under the terms of the GNU General Public License as published by
  11 the Free Software Foundation, either version 3 of the License, or (at
  12 your option) any later version.
  13
  14 GNU Emacs is distributed in the hope that it will be useful,
  15 but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 GNU General Public License for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
  21
  22
  23 /**
  24  **  To be run as an emacs subprocess.  Input string that starts with:
  25  **    'z' -- resets the watch (to zero).
  26  **    'p' -- return time (on stdout) as string with format <sec>.<micro-sec>
  27  **    'q' -- exit.
  28  **
  29  **  abstraction : a stopwatch
  30  **  operations: reset_watch, get_time
  31  */
  32
  33 #define INLINE EXTERN_INLINE
  34 #include <config.h>
  35
  36 #include <inttypes.h>
  37 #include <stdlib.h>
  38
  39 #include <intprops.h>
  40 #include <systime.h>
  41 #include <unlocked-io.h>
  42
  43 static struct timespec TV1;
  44 static int watch_not_started = 1; /* flag */
  45 static char time_string[INT_STRLEN_BOUND (uintmax_t) + sizeof "."
  46                         + LOG10_TIMESPEC_RESOLUTION];
  47
  48 /* Reset the stopwatch to zero.  */
  49
  50 static void
  51 reset_watch (void)
  52 {
  53   TV1 = current_timespec ();
  54   watch_not_started = 0;
  55 }
  56
  57 /* This call returns the time since the last reset_watch call.  The time
  58    is returned as a string with the format  <seconds>.<nanoseconds>
  59    If reset_watch was not called yet, exit.  */
  60
  61 static char *
  62 get_time (void)
  63 {
  64   struct timespec TV2 = timespec_sub (current_timespec (), TV1);
  65   uintmax_t s = TV2.tv_sec;
  66   int ns = TV2.tv_nsec;
  67   if (watch_not_started)
  68     exit (EXIT_FAILURE);  /* call reset_watch first ! */
  69   sprintf (time_string, "%"PRIuMAX".%0*d", s, LOG10_TIMESPEC_RESOLUTION, ns);
  70   return time_string;
  71 }
  72 \f
  73 int
  74 main (void)
  75 {
  76   int c;
  77   while ((c = getchar ()) != EOF)
  78     {
  79       switch (c)
  80         {
  81         case 'z':
  82           reset_watch ();
  83           break;
  84         case 'p':
  85           puts (get_time ());
  86           break;
  87         case 'q':
  88           return EXIT_SUCCESS;
  89         }
  90       /* Anything remaining on the line is ignored.  */
  91       while (c != '\n' && c != EOF)
  92         c = getchar ();
  93     }
  94   return EXIT_FAILURE;
  95 }
  96
  97
  98 /* profile.c ends here */