Re: timevar: 1/3: expect that getrusage is available

[Akim Demaille]

Waiting for approval before pushing.

commit 65b74a02c39450878ac1c41b870e1188c4a0429e
Author: Akim Demaille <address@hidden>
Date:   Thu Oct 11 17:54:35 2018 +0200

    timevar: expect that getrusage is available
    
    Don't keep both times and getrusage as backend: both are guaranteed by
    gnulib, a single one suffices.  Using getrusage is open to possibly
    tracking other types of resources in the future.
    
    * modules/timevar (Depends-on): Add getrusage.
    (configure.ac): Remove gl_TIMEVAR.
    * m4/timevar.m4: Remove, rely on gnulib for getrusage.
    * lib/timevar.h (timevar_enabled): Clarify documentation.
    * lib/timevar.c: Remove all the code about times.
    Remove all the CPP guards about getrusage: expect it to be present
    (courtesy of gnulib).

diff --git a/ChangeLog b/ChangeLog
index cc617fa3f..d93c7b6b0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2018-10-12  Akim Demaille  <address@hidden>
+
+       timevar: expect that getrusage is available.
+       Don't keep both times and getrusage as backend: both are guaranteed by
+       gnulib, a single one suffices.  Using getrusage is open to possibly
+       tracking other types of resources in the future.
+       * modules/timevar (Depends-on): Add getrusage.
+       (configure.ac): Remove gl_TIMEVAR.
+       * m4/timevar.m4: Remove, rely on gnulib for getrusage.
+       * lib/timevar.h (timevar_enabled): Clarify documentation.
+       * lib/timevar.c: Remove all the code about times.
+       Remove all the CPP guards about getrusage: expect it to be present
+       (courtesy of gnulib).
+
 2018-10-11  Bruno Haible  <address@hidden>
 
        mountlist: Modernize platform lists.
diff --git a/lib/timevar.c b/lib/timevar.c
index 391802838..469db9cb1 100644
--- a/lib/timevar.c
+++ b/lib/timevar.c
@@ -26,6 +26,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/resource.h>
 #include <sys/time.h>
 #include <sys/times.h>
 
@@ -33,50 +34,6 @@
 #define _(msgid) gettext (msgid)
 #include "xalloc.h"
 
-#ifdef HAVE_SYS_RESOURCE_H
-# include <sys/resource.h>
-#endif
-
-/* Calculation of scale factor to convert ticks to microseconds.
-   We mustn't use CLOCKS_PER_SEC except with clock().  */
-#if HAVE_SYSCONF && defined _SC_CLK_TCK
-# define TICKS_PER_SECOND sysconf (_SC_CLK_TCK) /* POSIX 1003.1-1996 */
-#elif defined CLK_TCK
-# define TICKS_PER_SECOND CLK_TCK /* POSIX 1003.1-1988; obsolescent */
-#elif defined HZ
-# define TICKS_PER_SECOND HZ  /* traditional UNIX */
-#else
-# define TICKS_PER_SECOND 100 /* often the correct value */
-#endif
-
-/* Prefer times to getrusage to clock (each gives successively less
-   information).  */
-#if defined HAVE_TIMES
-# define USE_TIMES
-# define HAVE_USER_TIME
-# define HAVE_SYS_TIME
-# define HAVE_WALL_TIME
-#elif defined HAVE_GETRUSAGE
-# define USE_GETRUSAGE
-# define HAVE_USER_TIME
-# define HAVE_SYS_TIME
-#endif
-
-#if defined USE_TIMES && !defined HAVE_DECL_TIMES
-clock_t times (struct tms *);
-#elif defined USE_GETRUSAGE && !defined HAVE_DECL_GETRUSAGE
-int getrusage (int, struct rusage *);
-#endif
-
-/* libc is very likely to have snuck a call to sysconf() into one of
-   the underlying constants, and that can be very slow, so we have to
-   precompute them.  Whose wonderful idea was it to make all those
-   _constants_ variable at run time, anyway?  */
-#ifdef USE_TIMES
-static float ticks_to_msec;
-# define TICKS_TO_MSEC (1.0 / TICKS_PER_SECOND)
-#endif
-
 /* See timevar.h for an explanation of timing variables.  */
 
 int timevar_enabled = 0;
@@ -132,9 +89,7 @@ static struct timevar_stack_def *unused_stack_instances;
    element.  */
 static struct timevar_time_def start_time;
 
-/* Fill the current times into TIME.  The definition of this function
-   also defines any or all of the HAVE_USER_TIME, HAVE_SYS_TIME, and
-   HAVE_WALL_TIME macros.  */
+/* Fill the current times into TIME.  */
 
 static void
 set_to_current_time (struct timevar_time_def *now)
@@ -146,19 +101,13 @@ set_to_current_time (struct timevar_time_def *now)
   if (!timevar_enabled)
     return;
 
-  {
-#ifdef USE_TIMES
-    struct tms tms;
-    now->wall = times (&tms) * ticks_to_msec;
-    now->user = (tms.tms_utime + tms.tms_cutime) * ticks_to_msec;
-    now->sys  = (tms.tms_stime + tms.tms_cstime) * ticks_to_msec;
-#elif defined USE_GETRUSAGE
-    struct rusage rusage;
-    getrusage (RUSAGE_CHILDREN, &rusage);
-    now->user = rusage.ru_utime.tv_sec + rusage.ru_utime.tv_usec * 1e-6;
-    now->sys  = rusage.ru_stime.tv_sec + rusage.ru_stime.tv_usec * 1e-6;
-#endif
-  }
+  struct rusage rusage;
+  getrusage (RUSAGE_SELF, &rusage);
+  now->user = rusage.ru_utime.tv_sec + rusage.ru_utime.tv_usec * 1e-6;
+  now->sys  = rusage.ru_stime.tv_sec + rusage.ru_stime.tv_usec * 1e-6;
+  getrusage (RUSAGE_CHILDREN, &rusage);
+  now->user += rusage.ru_utime.tv_sec + rusage.ru_utime.tv_usec * 1e-6;
+  now->sys  += rusage.ru_stime.tv_sec + rusage.ru_stime.tv_usec * 1e-6;
 }
 
 /* Return the current time.  */
@@ -197,10 +146,6 @@ timevar_init ()
   timevars[identifier__].name = name__;
 #include "timevar.def"
 #undef DEFTIMEVAR
-
-#if defined USE_TIMES
-  ticks_to_msec = TICKS_TO_MSEC;
-#endif
 }
 
 void
@@ -337,8 +282,6 @@ timevar_get (timevar_id_t timevar,
 void
 timevar_print (FILE *fp)
 {
-  /* Only print stuff if we have some sort of time information.  */
-#if defined HAVE_USER_TIME || defined HAVE_SYS_TIME || defined HAVE_WALL_TIME
   if (!timevar_enabled)
     return;
 
@@ -386,41 +329,27 @@ timevar_print (FILE *fp)
       /* The timing variable name.  */
       fprintf (fp, " %-22s:", tv->name);
 
-# ifdef HAVE_USER_TIME
       /* Print user-mode time for this process.  */
       fprintf (fp, "%7.2f (%2.0f%%) usr",
                tv->elapsed.user,
                (total->user == 0 ? 0 : tv->elapsed.user / total->user) * 100);
-# endif
 
-# ifdef HAVE_SYS_TIME
       /* Print system-mode time for this process.  */
       fprintf (fp, "%7.2f (%2.0f%%) sys",
                tv->elapsed.sys,
                (total->sys == 0 ? 0 : tv->elapsed.sys / total->sys) * 100);
-# endif
 
-# ifdef HAVE_WALL_TIME
       /* Print wall clock time elapsed.  */
       fprintf (fp, "%7.2f (%2.0f%%) wall",
                tv->elapsed.wall,
                (total->wall == 0 ? 0 : tv->elapsed.wall / total->wall) * 100);
-# endif
 
       putc ('\n', fp);
     }
 
   /* Print total time.  */
   fprintf (fp, " %-22s:", timevars[tv_total].name);
-#ifdef HAVE_USER_TIME
   fprintf (fp, "%7.2f          ", total->user);
-#endif
-#ifdef HAVE_SYS_TIME
   fprintf (fp, "%7.2f          ", total->sys);
-#endif
-#ifdef HAVE_WALL_TIME
   fprintf (fp, "%7.2f\n", total->wall);
-#endif
-
-#endif /* defined HAVE_USER_TIME || defined HAVE_SYS_TIME || defined 
HAVE_WALL_TIME */
 }
diff --git a/lib/timevar.h b/lib/timevar.h
index 7c9258409..ff443fed6 100644
--- a/lib/timevar.h
+++ b/lib/timevar.h
@@ -124,7 +124,9 @@ void timevar_get (timevar_id_t timevar, struct 
timevar_time_def *elapsed);
 
 void timevar_print (FILE *fp);
 
-/* Set to to nonzero to enable timing variables.  */
+/* Set to to nonzero to enable timing variables.  All the timevar
+   functions make an early exit if timevar is disabled.  */
+
 extern int timevar_enabled;
 
 # ifdef  __cplusplus
diff --git a/m4/timevar.m4 b/m4/timevar.m4
deleted file mode 100644
index c790ed0a9..000000000
--- a/m4/timevar.m4
+++ /dev/null
@@ -1,47 +0,0 @@
-# -*- Autoconf -*-
-# Checks required to run `timevar', a time tracker.
-#
-# Copyright (C) 2002-2003, 2009-2015, 2018 Free Software Foundation,
-# Inc.
-#
-# This program 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.
-#
-# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
-
-# serial 3
-
-AC_DEFUN([gl_TIMEVAR],
-[AC_CHECK_HEADERS([sys/time.h sys/times.h])
- AC_CHECK_HEADERS([sys/resource.h], [], [],
-   [$ac_includes_default
-#if HAVE_SYS_TIME_H
-# include <sys/time.h>
-#endif
-#ifdef HAVE_SYS_TIMES_H
-# include <sys/times.h>
-#endif
-])
-AC_CHECK_FUNCS([times])
-
-AC_CHECK_DECLS([getrusage, times, clock, sysconf], [], [],
-[$ac_includes_default
-#if HAVE_SYS_TIME_H
-# include <sys/time.h>
-#endif
-#if HAVE_SYS_TIMES_H
-# include <sys/times.h>
-#endif
-#if HAVE_SYS_RESOURCE_H
-# include <sys/resource.h>
-#endif
-])
-])
diff --git a/modules/timevar b/modules/timevar
index f82b7e90a..8be1b8318 100644
--- a/modules/timevar
+++ b/modules/timevar
@@ -7,6 +7,7 @@ lib/timevar.c
 m4/timevar.m4
 
 Depends-on:
+getrusage
 gettext-h
 stdlib
 sys_time
@@ -14,9 +15,6 @@ sys_times
 times
 xalloc
 
-configure.ac:
-gl_TIMEVAR
-
 Makefile.am:
 lib_SOURCES += timevar.c timevar.def