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MDEV-23175: my_timer_milliseconds ftime deprecated - clock_gettime replacement

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Linux glibc has deprecated ftime resutlting in a compile error on Fedora-32.

Per manual clock_gettime is the suggested replacement. Because my_timer_milliseconds
is a relative time used by largely the perfomrance schema, CLOCK_MONOTONIC_COARSE
is used. This has been available since Linux-2.6.32.

The low overhead is shows in the unittest:

    $ unittest/mysys/my_rdtsc-t
    1..11
    # ----- Routine ---------------
    # myt.cycles.routine          :             5
    # myt.nanoseconds.routine     :            11
    # myt.microseconds.routine    :            13
    # myt.milliseconds.routine    :            18
    # myt.ticks.routine           :            17
    # ----- Frequency -------------
    # myt.cycles.frequency        :    3596597014
    # myt.nanoseconds.frequency   :    1000000000
    # myt.microseconds.frequency  :       1000000
    # myt.milliseconds.frequency  :          1039
    # myt.ticks.frequency         :           103
    # ----- Resolution ------------
    # myt.cycles.resolution       :             1
    # myt.nanoseconds.resolution  :             1
    # myt.microseconds.resolution :             1
    # myt.milliseconds.resolution :             1
    # myt.ticks.resolution        :             1
    # ----- Overhead --------------
    # myt.cycles.overhead         :           118
    # myt.nanoseconds.overhead    :           234
    # myt.microseconds.overhead   :           222
    # myt.milliseconds.overhead   :            30
    # myt.ticks.overhead          :          4946
    ok 1 - my_timer_init() did not crash
    ok 2 - The cycle timer is strictly increasing
    ok 3 - The cycle timer is implemented
    ok 4 - The nanosecond timer is increasing
    ok 5 - The nanosecond timer is implemented
    ok 6 - The microsecond timer is increasing
    ok 7 - The microsecond timer is implemented
    ok 8 - The millisecond timer is increasing
    ok 9 - The millisecond timer is implemented
    ok 10 - The tick timer is increasing
    ok 11 - The tick timer is implemented
This commit is contained in:
Daniel Black 2020-07-15 11:23:19 +10:00 • committed by Eugene Kosov
parent e67daa5653
commit 20512a68d8
2 changed files with 16 additions and 3 deletions
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5
configure.cmake
View file

@ -441,9 +441,12 @@ CHECK_INCLUDE_FILES(ia64intrin.h HAVE_IA64INTRIN_H)
CHECK_FUNCTION_EXISTS(times HAVE_TIMES)
CHECK_FUNCTION_EXISTS(gettimeofday HAVE_GETTIMEOFDAY)
CHECK_FUNCTION_EXISTS(read_real_time HAVE_READ_REAL_TIME)
# This should work on AIX.
IF(NOT HAVE_CLOCK_GETTIME)
# This should work on AIX.
CHECK_FUNCTION_EXISTS(ftime HAVE_FTIME)
ENDIF()
# This is still a normal call for milliseconds.
CHECK_FUNCTION_EXISTS(time HAVE_TIME)

14
mysys/my_rdtsc.c
View file

@ -75,7 +75,7 @@
#endif
#endif
#if defined(HAVE_SYS_TIMEB_H) && defined(HAVE_FTIME)
#if !defined(CLOCK_GETTIME) && defined(HAVE_SYS_TIMEB_H) && defined(HAVE_FTIME)
#include <sys/timeb.h> /* for ftime */
#endif
@ -175,7 +175,17 @@ ulonglong my_timer_microseconds(void)
ulonglong my_timer_milliseconds(void)
{
#if defined(HAVE_SYS_TIMEB_H) && defined(HAVE_FTIME)
#if defined(HAVE_CLOCK_GETTIME)
struct timespec tp;
#ifdef CLOCK_MONOTONIC_COARSE
/* Linux */
clock_gettime(CLOCK_MONOTONIC_COARSE, &tp);
#else
/* POSIX */
clock_gettime(CLOCK_MONOTONIC, &tp);
#endif
return (ulonglong)tp.tv_sec * 1000 + (ulonglong)tp.tv_nsec / 1000000;
#elif defined(HAVE_SYS_TIMEB_H) && defined(HAVE_FTIME)
/* ftime() is obsolete but maybe the platform is old */
struct timeb ft;
ftime(&ft);