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Overview
| Comment: | NRT relevant only: provides self-calibrating mechanism for TclpUSleep (the actual time of usleep/nanosleep may be longer, due to system latencies and possible limitations in the timer resolution of the hardware); forces context switch or yield the processor if sleep time to small. |
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| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | sebres-8-5-event-perf-branch |
| Files: | files | file ages | folders |
| SHA3-256: |
9ce15c7f1acd585fd94ab1fac058c1e5 |
| User & Date: | sebres 2019-03-09 21:04:55.414 |
Context
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2019-05-22
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| 09:18 | merge 8.5 check-in: ba97c71d8f user: sebres tags: sebres-8-5-event-perf-branch | |
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2019-03-09
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| 21:22 | merge 8-5-event-perf-branch check-in: 697065a8e5 user: sebres tags: sebres-8-6-event-perf-branch | |
| 21:04 | NRT relevant only: provides self-calibrating mechanism for TclpUSleep (the actual time of usleep/nan... check-in: 9ce15c7f1a user: sebres tags: sebres-8-5-event-perf-branch | |
| 20:07 | non-native time scale fixed: do scale time only once (not in cycle, since all other times used in ca... check-in: f20b5264a3 user: sebres tags: sebres-8-5-event-perf-branch | |
Changes
Changes to unix/tclUnixNotfy.c.
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843 844 845 846 847 848 849 | * * Note: Adjusting of this values may increase NRT-capability, but also may * increase CPU load (resp. busy waits on brief intervals). */ #ifndef TCL_TMR_MIN_DELAY # define TCL_TMR_MIN_DELAY 100 | | > > > > > > | 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 |
*
* Note: Adjusting of this values may increase NRT-capability, but also may
* increase CPU load (resp. busy waits on brief intervals).
*/
#ifndef TCL_TMR_MIN_DELAY
# define TCL_TMR_MIN_DELAY 100
# define TCL_TMR_MIN_USLEEP 50
# define TCL_TMR_MIN_NSLEEP 1
# define TCL_TMR_OVERHEAD 50
#endif
/*
*----------------------------------------------------------------------
*
* TclpUSleep --
*
* Delay execution for the specified time (in microseconds).
*
* Results:
* None.
*
* Side effects:
* Time passes.
*
*----------------------------------------------------------------------
*/
static unsigned int tclMinDelay = TCL_TMR_MIN_DELAY;
static unsigned int tclMinUSleep = TCL_TMR_MIN_USLEEP;
static unsigned int tclMinNSleep = TCL_TMR_MIN_NSLEEP;
void
TclpUSleep(
Tcl_WideInt usec) /* Time to sleep. */
{
Tcl_WideInt now, desired;
unsigned int *calibValue;
if (usec < 0) {
usec = 0;
}
/*
* TIP #233: Scale from virtual time to real-time for select/usleep.
|
| ︙ | ︙ | |||
893 894 895 896 897 898 899 |
now = TclpGetUTimeMonotonic();
if ((desired = (now + usec)) < now) { /* overflow */
desired = 0x7FFFFFFFFFFFFFFFL;
}
while (1) {
| | > > | > > | | < < > > > > > > > > > > > > > | 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 |
now = TclpGetUTimeMonotonic();
if ((desired = (now + usec)) < now) { /* overflow */
desired = 0x7FFFFFFFFFFFFFFFL;
}
while (1) {
if (usec >= tclMinDelay) {
struct timeval delay;
calibValue = &tclMinDelay;
usec -= (usec % tclMinDelay);
delay.tv_sec = usec / 1000000;
delay.tv_usec = usec % 1000000;
(void) select(0, (SELECT_MASK *) 0, (SELECT_MASK *) 0,
(SELECT_MASK *) 0, &delay);
} else if (usec >= tclMinUSleep) {
calibValue = &tclMinUSleep;
usec -= (usec % tclMinUSleep);
usleep((useconds_t)usec);
} else if (usec >= tclMinNSleep) {
struct timespec delay;
calibValue = &tclMinNSleep;
usec -= (usec % tclMinNSleep);
delay.tv_sec = usec / 1000000;
delay.tv_nsec = (usec % 1000000) * 1000; /* usec to nsec */
nanosleep(&delay, NULL);
} else {
calibValue = NULL;
#ifdef _POSIX_PRIORITY_SCHEDULING
sched_yield(); /* yield the processor (force context switch). */
#endif
}
now = TclpGetUTimeMonotonic();
if ((usec = (desired - now)) <= 0 /* or tolerance */) {
/*
* Self calibration - sleep was too long, so adjust related value.
*/
if (calibValue && (unsigned int)-usec > *calibValue) {
*calibValue = (*calibValue + (unsigned int)-usec) / 2;
}
/* end of sleep */
break;
}
}
}
/*
*----------------------------------------------------------------------
|
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