Re: timevar: 3/3: use clock_gettime to get wall clock time

[Akim Demaille]

On macOS, I get an unexpected result for wall clock.

Execution times (seconds)
                          CPU user      CPU system    wall clock      
 reader                   0,017 ( 4%)   0,002 (13%)   0,000000 ( 0%)
 LALR(1)                  0,002 ( 0%)   0,000 ( 1%)   0,031250 ( 6%)
 outputting report        0,027 ( 5%)   0,002 (13%)   0,031250 ( 6%)
 parser action tables     0,018 ( 4%)   0,001 ( 7%)   0,000000 ( 0%)
 outputting parser        0,012 ( 2%)   0,001 (10%)   0,062500 (12%)
 running m4               0,407 (84%)   0,008 (54%)   0,375000 (75%)
 total time               0,488         0,014         0,500000

commit 48624ae07a9fa3c9d79a92b39e7ca31b4fb0c263
Author: Akim Demaille <akim.demai...@gmail.com>
Date:   Fri Oct 12 06:46:09 2018 +0200

    timevar: use clock_gettime to get wall clock time
    
    * modules/timevar (Depends-on): We need time.h.
    We no longer use times().
    * lib/timevar.c (set_to_current_time): Use clock_gettime.

diff --git a/ChangeLog b/ChangeLog
index 369848b12..bb550a54b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2018-10-12  Akim Demaille  <a...@lrde.epita.fr>
+
+       timevar: use clock_gettime to get wall clock time
+       * modules/timevar (Depends-on): We need time.h.
+       We no longer use times().
+       * lib/timevar.c (set_to_current_time): Use clock_gettime.
+
 2018-10-12  Akim Demaille  <a...@lrde.epita.fr>
 
        timevar: improve the output format
diff --git a/lib/timevar.c b/lib/timevar.c
index 8b574e277..13fa6bf75 100644
--- a/lib/timevar.c
+++ b/lib/timevar.c
@@ -29,6 +29,7 @@
 #include <sys/resource.h>
 #include <sys/time.h>
 #include <sys/times.h>
+#include <time.h>
 
 #include "gettext.h"
 #define _(msgid) gettext (msgid)
@@ -108,6 +109,10 @@ set_to_current_time (struct timevar_time_def *now)
   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;
+
+  struct timespec timespec;
+  clock_gettime(CLOCK_MONOTONIC, &timespec);
+  now->wall = timespec.tv_sec + timespec.tv_nsec * 1e-9;
 }
 
 /* Return the current time.  */
diff --git a/modules/timevar b/modules/timevar
index 8be1b8318..d0712720b 100644
--- a/modules/timevar
+++ b/modules/timevar
@@ -12,7 +12,7 @@ gettext-h
 stdlib
 sys_time
 sys_times
-times
+time
 xalloc
 
 Makefile.am: