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Reduce adjtime calling

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Don't call adjtime to determine remaining offset when there is no slewing
running.
This commit is contained in:
Miroslav Lichvar 2009-11-23 17:23:43 +01:00
parent 4097ab29c7
commit 62fe343990
1 changed files with 50 additions and 30 deletions
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58
sys_linux.c
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@ -143,6 +143,9 @@ our_lround(double x) {
/* Amount of outstanding offset to process */
static double offset_register;
/* Flag set true if an adjtime slew was started and still may be running */
static int slow_slewing;
/* Flag set true if a fast slew (one done by altering tick) is being
run at the moment */
static int fast_slewing;
@ -267,11 +270,14 @@ initiate_slew(void)
}
/* Cancel any standard adjtime that is running */
if (slow_slewing) {
offset = 0;
if (TMX_ApplyOffset(&offset) < 0) {
CROAK("adjtimex() failed in accrue_offset");
}
offset_register -= (double) offset / 1.0e6;
slow_slewing = 0;
}
if (fabs(offset_register) < MAX_ADJUST_WITH_ADJTIME) {
/* Use adjtime to do the shift */
@ -279,9 +285,12 @@ initiate_slew(void)
offset_register += offset * 1e-6;
if (offset != 0) {
if (TMX_ApplyOffset(&offset) < 0) {
CROAK("adjtimex() failed in initiate_slew");
}
slow_slewing = 1;
}
} else {
/* If the system clock has a high drift rate, the combination of
@ -540,37 +549,47 @@ get_offset_correction(struct timeval *raw,
double fast_slew_duration;
double fast_slew_achieved;
double fast_slew_remaining;
long offset;
long offset, toffset;
if (!slow_slewing) {
offset = 0;
} else {
again:
if (have_readonly_adjtime == 1) {
if (TMX_GetOffsetLeftOld(&offset) < 0) {
CROAK("adjtimex() failed in get_offset_correction");
}
adjtime_left = (double)offset / 1.0e6;
} else if (have_readonly_adjtime == 2) {
switch (have_readonly_adjtime) {
case 2:
if (TMX_GetOffsetLeft(&offset) < 0) {
LOG(LOGS_INFO, LOGF_SysLinux, "adjtimex() doesn't support ADJ_OFFSET_SS_READ");
have_readonly_adjtime = 0;
goto again;
}
adjtime_left = (double)offset / 1.0e6;
} else {
offset = 0;
if (TMX_ApplyOffset(&offset) < 0) {
break;
case 0:
toffset = 0;
if (TMX_ApplyOffset(&toffset) < 0) {
CROAK("adjtimex() failed in get_offset_correction");
}
offset = toffset;
if (TMX_ApplyOffset(&toffset) < 0) {
CROAK("adjtimex() failed in get_offset_correction");
}
break;
case 1:
if (TMX_GetOffsetLeftOld(&offset) < 0) {
CROAK("adjtimex() failed in get_offset_correction");
}
break;
default:
assert(0);
}
if (offset == 0) {
/* adjtime slew has finished */
slow_slewing = 0;
}
}
adjtime_left = (double)offset / 1.0e6;
/* txc.offset still set from return value of last call */
if (TMX_ApplyOffset(&offset) < 0) {
CROAK("adjtimex() failed in get_offset_correction");
}
}
if (fast_slewing) {
UTI_DiffTimevalsToDouble(&fast_slew_duration, raw, &slew_start_tv);
fast_slew_achieved = delta_total_tick * fast_slew_duration /
@ -604,6 +623,7 @@ immediate_step(void)
}
offset_register -= (double) offset / 1.0e6;
slow_slewing = 0;
if (gettimeofday(&old_time, &tz) < 0) {
CROAK("gettimeofday() failed in immediate_step");