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phc2sys: remove unnecessary clock step with non-PPS loops. 

With non-PPS loops let the servo make the inital correction. Move the
code to the PPS loop and change it to use the sample filtering to reduce
the error in the initial correction.

Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
master
Miroslav Lichvar 2013-01-14 17:09:15 +01:00 committed by Richard Cochran
parent fc1a695493
commit f09b4bb7e3
1 changed files with 14 additions and 10 deletions
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24
phc2sys.c
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@ -195,7 +195,8 @@ static int read_pps(int fd, int64_t *offset, uint64_t *ts)
return 1; return 1;
} }
static int do_pps_loop(struct clock *clock, char *pps_device) static int do_pps_loop(struct clock *clock, char *pps_device,
clockid_t src, int n_readings, int sync_offset)
{ {
int64_t pps_offset; int64_t pps_offset;
uint64_t pps_ts; uint64_t pps_ts;
@ -208,6 +209,16 @@ static int do_pps_loop(struct clock *clock, char *pps_device)
fprintf(stderr, "cannot open '%s': %m\n", pps_device); fprintf(stderr, "cannot open '%s': %m\n", pps_device);
return -1; return -1;
} }
/* Make the initial sync from PHC if available. */
if (src != CLOCK_INVALID) {
if (!read_phc(src, clock->clkid, n_readings,
&pps_offset, &pps_ts))
return -1;
pps_offset -= sync_offset * NS_PER_SEC;
clock_step(clock->clkid, -pps_offset);
}
while (1) { while (1) {
if (!read_pps(fd, &pps_offset, &pps_ts)) { if (!read_pps(fd, &pps_offset, &pps_ts)) {
continue; continue;
@ -355,14 +366,6 @@ int main(int argc, char *argv[])
usage(progname); usage(progname);
return -1; return -1;
} }
if (src != CLOCK_INVALID) {
struct timespec now;
if (clock_gettime(src, &now))
perror("clock_gettime");
now.tv_sec += sync_offset;
if (clock_settime(dst_clock.clkid, &now))
perror("clock_settime");
}
ppb = clock_ppb_read(dst_clock.clkid); ppb = clock_ppb_read(dst_clock.clkid);
/* The reading may silently fail and return 0, reset the frequency to /* The reading may silently fail and return 0, reset the frequency to
@ -372,7 +375,8 @@ int main(int argc, char *argv[])
dst_clock.servo = servo_create(CLOCK_SERVO_PI, -ppb, max_ppb, 0); dst_clock.servo = servo_create(CLOCK_SERVO_PI, -ppb, max_ppb, 0);
if (device) if (device)
return do_pps_loop(&dst_clock, device); return do_pps_loop(&dst_clock, device, src,
phc_readings, sync_offset);
if (dst_clock.clkid == CLOCK_REALTIME && if (dst_clock.clkid == CLOCK_REALTIME &&
SYSOFF_SUPPORTED == sysoff_probe(CLOCKID_TO_FD(src), phc_readings)) SYSOFF_SUPPORTED == sysoff_probe(CLOCKID_TO_FD(src), phc_readings))