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| author | phk <phk@FreeBSD.org> | 2000-01-04 12:04:39 +0000 |
|---|---|---|
| committer | phk <phk@FreeBSD.org> | 2000-01-04 12:04:39 +0000 |
| commit | 325c58929addcc4459a0dbcf440b7619b0234364 (patch) | |
| tree | c279d408fa7d2fa9c705d9a625f58375623660b5 /sys/kern | |
| parent | a8574b388890db2212e4cff87aaf3be885cd83e8 (diff) | |
| download | FreeBSD-src-325c58929addcc4459a0dbcf440b7619b0234364.zip FreeBSD-src-325c58929addcc4459a0dbcf440b7619b0234364.tar.gz | |
Create a separate pps_offset variable to use for applying the
hardpps() produced offset component. This is tested and behaved
stable with frequency offsets from -338.05 to +499.91 PPM.
Interestingly the machine I tested this on would fail if the clock
were slower than 14.3132 MHz whereas it was perfectly happy to run
at 16.384 MHz, in other words [-340PPM ... +14.4%]
Make pps_shift tweakable with sysctl.
Diffstat (limited to 'sys/kern')
| -rw-r--r-- | sys/kern/kern_ntptime.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/sys/kern/kern_ntptime.c b/sys/kern/kern_ntptime.c index 36394ee..71b55f4 100644 --- a/sys/kern/kern_ntptime.c +++ b/sys/kern/kern_ntptime.c @@ -163,6 +163,7 @@ static l_fp time_freq; /* frequency offset (ns/s) */ #define PPS_POPCORN 2 /* popcorn spike threshold (shift) */ static struct timespec pps_tf[3]; /* phase median filter */ +static l_fp pps_offset; /* time offset (ns) */ static l_fp pps_freq; /* scaled frequency offset (ns/s) */ static long pps_fcount; /* frequency accumulator */ static long pps_jitter; /* nominal jitter (ns) */ @@ -245,6 +246,7 @@ SYSCTL_PROC(_kern_ntp_pll, OID_AUTO, gettime, CTLTYPE_OPAQUE|CTLFLAG_RD, #ifdef PPS_SYNC SYSCTL_INT(_kern_ntp_pll, OID_AUTO, pps_shiftmax, CTLFLAG_RW, &pps_shiftmax, 0, ""); +SYSCTL_INT(_kern_ntp_pll, OID_AUTO, pps_shift, CTLFLAG_RW, &pps_shift, 0, ""); #endif /* * ntp_adjtime() - NTP daemon application interface @@ -479,15 +481,19 @@ ntp_update_second(struct timecounter *tcp) * value is in effect scaled by the clock frequency, * since the adjustment is added at each tick interrupt. */ - time_adj = time_offset; #ifdef PPS_SYNC + /* XXX even if signal dies we should finish adjustment ? */ if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL) { + time_adj = pps_offset; L_RSHIFT(time_adj, pps_shift); + L_SUB(pps_offset, time_adj); } else { + time_adj = time_offset; L_RSHIFT(time_adj, SHIFT_PLL + time_constant); L_SUB(time_offset, time_adj); } #else + time_adj = time_offset; L_RSHIFT(time_adj, SHIFT_PLL + time_constant); L_SUB(time_offset, time_adj); #endif /* PPS_SYNC */ @@ -731,6 +737,7 @@ hardpps(tsp, nsec) pps_jitcnt++; } else if (time_status & STA_PPSTIME) { L_LINT(time_offset, -v_nsec); + L_LINT(pps_offset, -v_nsec); } pps_jitter += (u_nsec - pps_jitter) >> PPS_FAVG; u_sec = pps_tf[0].tv_sec - pps_lastsec; |
