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scm_c_get_internal_run_time is more precise

* libguile/stime.h (SCM_TIME_UNITS_PER_SECOND): Redefine to point to a C
  variable instead of being a pure preprocessor thing.  This has the
  possibility to break existing compiled C extensions' interpretation of
  the internal-time-units-per-second, but hopefully there's no too much
  of that code out there, and in the worst case they can just
  recompile.  Scheme code will get it right without the need to
  recompile.

* libguile/stime.c (TIME_UNITS_PER_SECOND): New local define, and
  increase to nanosecond resolution if we are on a system in which this
  is useful and practical.
  (time_from_seconds_and_nanoseconds): New helper.
  (get_internal_real_time, get_internal_run_time): New global vars:
  function pointers.
  (get_internal_real_time_posix_timer):
  (get_internal_run_time_posix_timer):
  (get_internal_real_time_gettimeofday):
  (get_internal_run_time_times):
  (get_internal_real_time_fallback): Various implementations.
  (scm_get_internal_real_time): Return the get_internal_real_time()
  result.
  (scm_c_get_internal_run_time): Likewise.
  (scm_gettimeofday): No need for a critical section, and remove
  obsolete ftime block.
  (scm_init_stime): Init all of the new time bases, and decide on
  implementations of real time and run time accessors.
This commit is contained in:
Andy Wingo 2011-05-04 20:15:23 +02:00
parent e3b8bce8f4
commit 4a42658f6a
2 changed files with 169 additions and 105 deletions

View file

@ -64,9 +64,13 @@
#endif
# ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
# endif
#ifdef HAVE_CLOCK_GETTIME
# include <time.h>
#endif
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
@ -98,27 +102,98 @@ extern char *strptime ();
#endif
#ifdef HAVE_TIMES
static
timet mytime()
#if SCM_SIZEOF_LONG >= 8 && defined HAVE_CLOCK_GETTIME
/* Nanoseconds on 64-bit systems with POSIX timers. */
#define TIME_UNITS_PER_SECOND 1000000000
#else
/* Milliseconds for everyone else. */
#define TIME_UNITS_PER_SECOND 1000
#endif
long scm_c_time_units_per_second = TIME_UNITS_PER_SECOND;
static long
time_from_seconds_and_nanoseconds (long s, long ns)
{
return s * TIME_UNITS_PER_SECOND
+ ns / (1000000000 / TIME_UNITS_PER_SECOND);
}
/* A runtime-selectable mechanism to choose a timing mechanism. Really
we want to use POSIX timers, but that's not always possible. Notably,
the user may have everything she needs at compile-time, but if she's
running on an SMP machine without a common clock source, she can't
use POSIX CPUTIME clocks. */
static long (*get_internal_real_time) (void);
static long (*get_internal_run_time) (void);
#ifdef HAVE_CLOCK_GETTIME
struct timespec posix_real_time_base;
static long
get_internal_real_time_posix_timer (void)
{
struct timespec ts;
clock_gettime (CLOCK_REALTIME, &ts);
return time_from_seconds_and_nanoseconds
(ts.tv_sec - posix_real_time_base.tv_sec,
ts.tv_nsec - posix_real_time_base.tv_nsec);
}
#ifdef _POSIX_CPUTIME
struct timespec posix_run_time_base;
static long
get_internal_run_time_posix_timer (void)
{
struct timespec ts;
clock_gettime (CLOCK_PROCESS_CPUTIME_ID, &ts);
return time_from_seconds_and_nanoseconds
(ts.tv_sec - posix_run_time_base.tv_sec,
ts.tv_nsec - posix_run_time_base.tv_nsec);
}
#endif /* _POSIX_CPUTIME */
#endif /* HAVE_CLOCKTIME */
#ifdef HAVE_GETTIMEOFDAY
struct timeval gettimeofday_real_time_base;
static long
get_internal_real_time_gettimeofday (void)
{
struct timeval tv;
gettimeofday (&tv, NULL);
return time_from_seconds_and_nanoseconds
(tv.tv_sec - gettimeofday_real_time_base.tv_sec,
(tv.tv_usec - gettimeofday_real_time_base.tv_usec) * 1000);
}
#endif
#if defined HAVE_TIMES
static long ticks_per_second;
static long
get_internal_run_time_times (void)
{
struct tms time_buffer;
times(&time_buffer);
return time_buffer.tms_utime + time_buffer.tms_stime;
return (time_buffer.tms_utime + time_buffer.tms_stime)
* TIME_UNITS_PER_SECOND / ticks_per_second;
}
#else
# ifdef LACK_CLOCK
# define mytime() ((time((timet*)0) - scm_your_base) * SCM_TIME_UNITS_PER_SECOND)
# else
# define mytime clock
# endif
#endif
#ifdef HAVE_FTIME
struct timeb scm_your_base = {0};
#else
timet scm_your_base = 0;
#endif
static timet fallback_real_time_base;
static long
get_internal_real_time_fallback (void)
{
return time_from_seconds_and_nanoseconds
((long) time (NULL) - fallback_real_time_base, 0);
}
SCM_DEFINE (scm_get_internal_real_time, "get-internal-real-time", 0, 0, 0,
(),
@ -126,23 +201,7 @@ SCM_DEFINE (scm_get_internal_real_time, "get-internal-real-time", 0, 0, 0,
"started.")
#define FUNC_NAME s_scm_get_internal_real_time
{
#ifdef HAVE_FTIME
struct timeb time_buffer;
SCM tmp;
ftime (&time_buffer);
time_buffer.time -= scm_your_base.time;
tmp = scm_from_long (time_buffer.millitm - scm_your_base.millitm);
tmp = scm_sum (tmp,
scm_product (scm_from_int (1000),
scm_from_int (time_buffer.time)));
return scm_quotient (scm_product (tmp,
scm_from_int (SCM_TIME_UNITS_PER_SECOND)),
scm_from_int (1000));
#else
return scm_from_long ((time((timet*)0) - scm_your_base)
* (int)SCM_TIME_UNITS_PER_SECOND);
#endif /* HAVE_FTIME */
return scm_from_long (get_internal_real_time ());
}
#undef FUNC_NAME
@ -175,27 +234,35 @@ SCM_DEFINE (scm_times, "times", 0, 0, 0,
{
struct tms t;
clock_t rv;
SCM factor;
SCM result = scm_c_make_vector (5, SCM_UNDEFINED);
rv = times (&t);
if (rv == -1)
SCM_SYSERROR;
SCM_SIMPLE_VECTOR_SET (result, 0, scm_from_long (rv));
SCM_SIMPLE_VECTOR_SET (result, 1, scm_from_long (t.tms_utime));
SCM_SIMPLE_VECTOR_SET (result, 2, scm_from_long (t.tms_stime));
SCM_SIMPLE_VECTOR_SET (result ,3, scm_from_long (t.tms_cutime));
SCM_SIMPLE_VECTOR_SET (result, 4, scm_from_long (t.tms_cstime));
factor = scm_quotient (scm_from_long (TIME_UNITS_PER_SECOND),
scm_from_long (ticks_per_second));
SCM_SIMPLE_VECTOR_SET (result, 0,
scm_product (scm_from_long (rv), factor));
SCM_SIMPLE_VECTOR_SET (result, 1,
scm_product (scm_from_long (t.tms_utime), factor));
SCM_SIMPLE_VECTOR_SET (result, 2,
scm_product (scm_from_long (t.tms_stime), factor));
SCM_SIMPLE_VECTOR_SET (result ,3,
scm_product (scm_from_long (t.tms_cutime), factor));
SCM_SIMPLE_VECTOR_SET (result, 4,
scm_product (scm_from_long (t.tms_cstime), factor));
return result;
}
#undef FUNC_NAME
#endif /* HAVE_TIMES */
static long scm_my_base = 0;
long
scm_c_get_internal_run_time ()
scm_c_get_internal_run_time (void)
{
return mytime () - scm_my_base;
return get_internal_run_time ();
}
SCM_DEFINE (scm_get_internal_run_time, "get-internal-run-time", 0, 0, 0,
@ -243,41 +310,18 @@ SCM_DEFINE (scm_gettimeofday, "gettimeofday", 0, 0, 0,
{
#ifdef HAVE_GETTIMEOFDAY
struct timeval time;
int ret, err;
SCM_CRITICAL_SECTION_START;
ret = gettimeofday (&time, NULL);
err = errno;
SCM_CRITICAL_SECTION_END;
if (ret == -1)
{
errno = err;
SCM_SYSERROR;
}
if (gettimeofday (&time, NULL))
SCM_SYSERROR;
return scm_cons (scm_from_long (time.tv_sec),
scm_from_long (time.tv_usec));
#else
# ifdef HAVE_FTIME
struct timeb time;
ftime(&time);
return scm_cons (scm_from_long (time.time),
scm_from_int (time.millitm * 1000));
# else
timet timv;
int err;
SCM_CRITICAL_SECTION_START;
timv = time (NULL);
err = errno;
SCM_CRITICAL_SECTION_END;
if (timv == -1)
{
errno = err;
SCM_SYSERROR;
}
return scm_cons (scm_from_long (timv), scm_from_int (0));
# endif
timet t = time (NULL);
if (errno)
SCM_SYSERROR;
else
return scm_cons (scm_from_long ((long)t), SCM_INUM0);
#endif
}
#undef FUNC_NAME
@ -798,13 +842,55 @@ scm_init_stime()
scm_c_define ("internal-time-units-per-second",
scm_from_long (SCM_TIME_UNITS_PER_SECOND));
#ifdef HAVE_FTIME
if (!scm_your_base.time) ftime(&scm_your_base);
#else
if (!scm_your_base) time(&scm_your_base);
/* Init POSIX timers, and see if we can use them. */
#ifdef HAVE_CLOCK_GETTIME
if (clock_gettime (CLOCK_REALTIME, &posix_real_time_base) == 0)
get_internal_real_time = get_internal_real_time_posix_timer;
#ifdef _POSIX_CPUTIME
{
clockid_t dummy;
/* Only use the _POSIX_CPUTIME clock if it's going to work across
CPUs. */
if (clock_getcpuclockid (0, &dummy) == 0 &&
clock_gettime (CLOCK_PROCESS_CPUTIME_ID, &posix_run_time_base) == 0)
get_internal_run_time = get_internal_run_time_posix_timer;
else
errno = 0;
}
#endif /* _POSIX_CPUTIME */
#endif /* HAVE_CLOCKTIME */
/* If needed, init and use gettimeofday timer. */
#ifdef HAVE_GETTIMEOFDAY
if (!get_internal_real_time
&& gettimeofday (&gettimeofday_real_time_base, NULL) == 0)
get_internal_real_time = get_internal_real_time_gettimeofday;
#endif
if (!scm_my_base) scm_my_base = mytime();
/* Init ticks_per_second for scm_times, and use times(2)-based
run-time timer if needed. */
#ifdef HAVE_TIMES
#ifdef _SC_CLK_TCK
ticks_per_second = sysconf (_SC_CLK_TCK);
#else
ticks_per_second = CLK_TCK;
#endif
if (!get_internal_run_time)
get_internal_run_time = get_internal_run_time_times;
#endif
if (!get_internal_real_time)
/* No POSIX timers, gettimeofday doesn't work... badness! */
{
fallback_real_time_base = time (NULL);
get_internal_real_time = get_internal_real_time_fallback;
}
/* If we don't have a run-time timer, use real-time. */
if (!get_internal_run_time)
get_internal_run_time = get_internal_real_time;
scm_add_feature ("current-time");
#include "libguile/stime.x"

View file

@ -3,7 +3,7 @@
#ifndef SCM_STIME_H
#define SCM_STIME_H
/* Copyright (C) 1995,1996,1997,1998,2000, 2003, 2006, 2008 Free Software Foundation, Inc.
/* Copyright (C) 1995,1996,1997,1998,2000, 2003, 2006, 2008, 2011 Free Software Foundation, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
@ -25,32 +25,10 @@
#include "libguile/__scm.h"
#include <unistd.h> /* for sysconf */
/* This should be figured out by autoconf.
sysconf(_SC_CLK_TCK) is best, since it's the actual running kernel, not
some compile-time CLK_TCK. On glibc 2.3.2 CLK_TCK (when defined) is in
fact sysconf(_SC_CLK_TCK) anyway.
CLK_TCK is obsolete in POSIX. In glibc 2.3.2 it's defined by default,
but if you define _GNU_SOURCE or _POSIX_C_SOURCE to get other features
then it goes away. */
#if ! defined(SCM_TIME_UNITS_PER_SECOND) && defined(_SC_CLK_TCK)
# define SCM_TIME_UNITS_PER_SECOND ((int) sysconf (_SC_CLK_TCK))
#endif
#if ! defined(SCM_TIME_UNITS_PER_SECOND) && defined(CLK_TCK)
# define SCM_TIME_UNITS_PER_SECOND ((int) CLK_TCK)
#endif
#if ! defined(SCM_TIME_UNITS_PER_SECOND) && defined(CLOCKS_PER_SEC)
# define SCM_TIME_UNITS_PER_SECOND ((int) CLOCKS_PER_SEC)
#endif
#if ! defined(SCM_TIME_UNITS_PER_SECOND)
# define SCM_TIME_UNITS_PER_SECOND 60
#endif
SCM_API long scm_c_time_units_per_second;
#define SCM_TIME_UNITS_PER_SECOND scm_c_time_units_per_second
SCM_API long scm_c_get_internal_run_time (void);