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ntp: include precision of PHC readings in their selection

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Include a fixed non-zero precision (100 nanosecond) in the selection of
PHC readings.
This commit is contained in:
Miroslav Lichvar 2017-01-19 12:24:49 +01:00
parent 7a937c7652
commit 98f5d05925
1 changed files with 11 additions and 8 deletions
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19
ntp_io_linux.c
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@ -66,6 +66,8 @@ struct Interface {
/* Start of UDP data at layer 2 for IPv4 and IPv6 */ /* Start of UDP data at layer 2 for IPv4 and IPv6 */
int l2_udp4_ntp_start; int l2_udp4_ntp_start;
int l2_udp6_ntp_start; int l2_udp6_ntp_start;
/* Precision of PHC readings */
double precision;
/* Compensation of errors in TX and RX timestamping */ /* Compensation of errors in TX and RX timestamping */
double tx_comp; double tx_comp;
double rx_comp; double rx_comp;
@ -173,6 +175,7 @@ add_interface(CNF_HwTsInterface *conf_iface)
iface->l2_udp4_ntp_start = 42; iface->l2_udp4_ntp_start = 42;
iface->l2_udp6_ntp_start = 62; iface->l2_udp6_ntp_start = 62;
iface->precision = 100.0e-9;
iface->tx_comp = conf_iface->tx_comp; iface->tx_comp = conf_iface->tx_comp;
iface->rx_comp = conf_iface->rx_comp; iface->rx_comp = conf_iface->rx_comp;
@ -342,7 +345,8 @@ NIO_Linux_SetTimestampSocketOptions(int sock_fd, int client_only, int *events)
/* ================================================== */ /* ================================================== */
static int static int
get_phc_sample(int phc_fd, struct timespec *phc_ts, struct timespec *local_ts, double *p_delay) get_phc_sample(struct Interface *iface, struct timespec *phc_ts, struct timespec *local_ts,
double *err)
{ {
struct ptp_sys_offset sys_off; struct ptp_sys_offset sys_off;
struct timespec ts1, ts2, ts3, phc_tss[PHC_READINGS], sys_tss[PHC_READINGS]; struct timespec ts1, ts2, ts3, phc_tss[PHC_READINGS], sys_tss[PHC_READINGS];
@ -354,7 +358,7 @@ get_phc_sample(int phc_fd, struct timespec *phc_ts, struct timespec *local_ts, d
sys_off.n_samples = PHC_READINGS; sys_off.n_samples = PHC_READINGS;
if (ioctl(phc_fd, PTP_SYS_OFFSET, &sys_off)) { if (ioctl(iface->phc_fd, PTP_SYS_OFFSET, &sys_off)) {
DEBUG_LOG(LOGF_NtpIOLinux, "ioctl(%s) failed : %s", "PTP_SYS_OFFSET", strerror(errno)); DEBUG_LOG(LOGF_NtpIOLinux, "ioctl(%s) failed : %s", "PTP_SYS_OFFSET", strerror(errno));
return 0; return 0;
} }
@ -383,7 +387,7 @@ get_phc_sample(int phc_fd, struct timespec *phc_ts, struct timespec *local_ts, d
/* Combine best readings */ /* Combine best readings */
for (i = n = 0, phc_sum = local_sum = 0.0; i < PHC_READINGS; i++) { for (i = n = 0, phc_sum = local_sum = 0.0; i < PHC_READINGS; i++) {
if (delays[i] > min_delay + local_prec) if (delays[i] > min_delay + MAX(local_prec, iface->precision))
continue; continue;
phc_sum += UTI_DiffTimespecsToDouble(&phc_tss[i], &phc_tss[0]); phc_sum += UTI_DiffTimespecsToDouble(&phc_tss[i], &phc_tss[0]);
@ -396,7 +400,7 @@ get_phc_sample(int phc_fd, struct timespec *phc_ts, struct timespec *local_ts, d
UTI_AddDoubleToTimespec(&phc_tss[0], phc_sum / n, phc_ts); UTI_AddDoubleToTimespec(&phc_tss[0], phc_sum / n, phc_ts);
UTI_AddDoubleToTimespec(&sys_tss[0], local_sum / n, &ts1); UTI_AddDoubleToTimespec(&sys_tss[0], local_sum / n, &ts1);
LCL_CookTime(&ts1, local_ts, NULL); LCL_CookTime(&ts1, local_ts, NULL);
*p_delay = min_delay; *err = MAX(min_delay / 2.0, iface->precision);
return 1; return 1;
} }
@ -427,15 +431,14 @@ process_hw_timestamp(struct Interface *iface, struct timespec *hw_ts,
NTP_Local_Timestamp *local_ts, int rx_ntp_length, int family) NTP_Local_Timestamp *local_ts, int rx_ntp_length, int family)
{ {
struct timespec sample_phc_ts, sample_local_ts, ts; struct timespec sample_phc_ts, sample_local_ts, ts;
double sample_delay, rx_correction, ts_delay, err; double rx_correction, ts_delay, err;
int l2_length; int l2_length;
if (HCL_NeedsNewSample(iface->clock, &local_ts->ts)) { if (HCL_NeedsNewSample(iface->clock, &local_ts->ts)) {
if (!get_phc_sample(iface->phc_fd, &sample_phc_ts, &sample_local_ts, &sample_delay)) if (!get_phc_sample(iface, &sample_phc_ts, &sample_local_ts, &err))
return; return;
HCL_AccumulateSample(iface->clock, &sample_phc_ts, &sample_local_ts, HCL_AccumulateSample(iface->clock, &sample_phc_ts, &sample_local_ts, err);
sample_delay / 2.0);
update_interface_speed(iface); update_interface_speed(iface);
} }