emo/busybox
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

ntpd: disable unused code; show kernel's clock drift correction

Browse Source 
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2010-01-01 19:56:16 +01:00
parent bfc2a32d88
commit 61313117a0
1 changed files with 38 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
networking/ntpd.c
View File

@ -49,7 +49,7 @@
#define RETRY_INTERVAL 5 /* on error, retry in N secs */ #define RETRY_INTERVAL 5 /* on error, retry in N secs */
#define QUERYTIME_MAX 15 /* wait for reply up to N secs */ #define QUERYTIME_MAX 15 /* wait for reply up to N secs */
#define FREQ_TOLERANCE 15e-6 /* % frequency tolerance (15 PPM) */ #define FREQ_TOLERANCE 0.000015 /* % frequency tolerance (15 PPM) */
#define MINPOLL 4 /* % minimum poll interval (6: 64 s) */ #define MINPOLL 4 /* % minimum poll interval (6: 64 s) */
#define MAXPOLL 12 /* % maximum poll interval (12: 1.1h, 17: 36.4h) (was 17) */ #define MAXPOLL 12 /* % maximum poll interval (12: 1.1h, 17: 36.4h) (was 17) */
#define MINDISP 0.01 /* % minimum dispersion (s) */ #define MINDISP 0.01 /* % minimum dispersion (s) */
@ -59,7 +59,7 @@
#define MIN_SELECTED 1 /* % minimum intersection survivors */ #define MIN_SELECTED 1 /* % minimum intersection survivors */
#define MIN_CLUSTERED 3 /* % minimum cluster survivors */ #define MIN_CLUSTERED 3 /* % minimum cluster survivors */
#define MAXFREQ 0.000500 /* frequency tolerance (500 PPM) */ #define MAXDRIFT 0.000500 /* frequency drift we can correct (500 PPM) */
/* Clock discipline parameters and constants */ /* Clock discipline parameters and constants */
#define STEP_THRESHOLD 0.128 /* step threshold (s) */ #define STEP_THRESHOLD 0.128 /* step threshold (s) */
@ -70,8 +70,8 @@
/* Poll-adjust threshold. /* Poll-adjust threshold.
* When we see that offset is small enough compared to discipline jitter, * When we see that offset is small enough compared to discipline jitter,
* we grow a counter: += MINPOLL. When it goes over POLLADJ_LIMIT, * we grow a counter: += MINPOLL. When it goes over POLLADJ_LIMIT,
* we poll_ext++. If offset isn't small, counter -= poll_ext*2, * we poll_exp++. If offset isn't small, counter -= poll_exp*2,
* and when it goes below -POLLADJ_LIMIT, we poll_ext-- * and when it goes below -POLLADJ_LIMIT, we poll_exp--
*/ */
#define POLLADJ_LIMIT 30 #define POLLADJ_LIMIT 30
/* If offset < POLLADJ_GATE * discipline_jitter, then we can increase /* If offset < POLLADJ_GATE * discipline_jitter, then we can increase
@ -88,6 +88,7 @@
/* Parameter averaging constant */ /* Parameter averaging constant */
#define AVG 4 #define AVG 4
enum { enum {
NTP_VERSION = 4, NTP_VERSION = 4,
NTP_MAXSTRATUM = 15, NTP_MAXSTRATUM = 15,
@ -251,13 +252,17 @@ struct globals {
uint8_t discipline_state; // doc calls it c.state uint8_t discipline_state; // doc calls it c.state
uint8_t poll_exp; // s.poll uint8_t poll_exp; // s.poll
int polladj_count; // c.count int polladj_count; // c.count
double discipline_jitter; // c.jitter long kernel_freq_drift;
double last_update_offset; // c.last double last_update_offset; // c.last
double last_update_recv_time; // s.t
double discipline_jitter; // c.jitter
//TODO: add s.jitter - grep for it here and see clock_combine() in doc
#define USING_KERNEL_PLL_LOOP 1
#if !USING_KERNEL_PLL_LOOP
double discipline_freq_drift; // c.freq double discipline_freq_drift; // c.freq
//TODO: conditionally calculate wander? it's used only for logging //TODO: conditionally calculate wander? it's used only for logging
double discipline_wander; // c.wander double discipline_wander; // c.wander
double last_update_recv_time; // s.t #endif
//TODO: add s.jitter - grep for it here and see clock_combine() in doc
}; };
#define G (*ptr_to_globals) #define G (*ptr_to_globals)
@ -1153,25 +1158,27 @@ update_local_clock(peer_t *p, double t)
* (Any other state does not reach this, they all return earlier) * (Any other state does not reach this, they all return earlier)
* By this time, freq_drift and G.last_update_offset are set * By this time, freq_drift and G.last_update_offset are set
* to values suitable for adjtimex. * to values suitable for adjtimex.
* */
* Calculate the new frequency drift and frequency stability (wander). #if !USING_KERNEL_PLL_LOOP
/* Calculate the new frequency drift and frequency stability (wander).
* Compute the clock wander as the RMS of exponentially weighted * Compute the clock wander as the RMS of exponentially weighted
* frequency differences. This is not used directly, but can, * frequency differences. This is not used directly, but can,
* along with the jitter, be a highly useful monitoring and * along with the jitter, be a highly useful monitoring and
* debugging tool. * debugging tool.
*/ */
dtemp = G.discipline_freq_drift + freq_drift; dtemp = G.discipline_freq_drift + freq_drift;
G.discipline_freq_drift = MAXD(MIND(MAXFREQ, dtemp), -MAXFREQ); G.discipline_freq_drift = MAXD(MIND(MAXDRIFT, dtemp), -MAXDRIFT);
etemp = SQUARE(G.discipline_wander); etemp = SQUARE(G.discipline_wander);
dtemp = SQUARE(dtemp); dtemp = SQUARE(dtemp);
G.discipline_wander = SQRT(etemp + (dtemp - etemp) / AVG); G.discipline_wander = SQRT(etemp + (dtemp - etemp) / AVG);
VERB3 { VERB3 bb_error_msg("discipline freq_drift=%.9f(int:%ld corr:%e) wander=%f",
bb_error_msg("discipline freq_drift=%.9f(int:%ld corr:%e) wander=%f",
G.discipline_freq_drift, G.discipline_freq_drift,
(long)(G.discipline_freq_drift * 65536e6), (long)(G.discipline_freq_drift * 65536e6),
freq_drift, freq_drift,
G.discipline_wander); G.discipline_wander);
#endif
VERB3 {
memset(&tmx, 0, sizeof(tmx)); memset(&tmx, 0, sizeof(tmx));
if (adjtimex(&tmx) < 0) if (adjtimex(&tmx) < 0)
bb_perror_msg_and_die("adjtimex"); bb_perror_msg_and_die("adjtimex");
@ -1192,7 +1199,7 @@ update_local_clock(peer_t *p, double t)
} }
memset(&tmx, 0, sizeof(tmx)); memset(&tmx, 0, sizeof(tmx));
#if 0 #if 0
//doesn't work, offset remains 0 (!): //doesn't work, offset remains 0 (!) in kernel:
//ntpd: set adjtimex freq:1786097 tmx.offset:77487 //ntpd: set adjtimex freq:1786097 tmx.offset:77487
//ntpd: prev adjtimex freq:1786097 tmx.offset:0 //ntpd: prev adjtimex freq:1786097 tmx.offset:0
//ntpd: cur adjtimex freq:1786097 tmx.offset:0 //ntpd: cur adjtimex freq:1786097 tmx.offset:0
@ -1218,14 +1225,21 @@ update_local_clock(peer_t *p, double t)
rc = adjtimex(&tmx); rc = adjtimex(&tmx);
if (rc < 0) if (rc < 0)
bb_perror_msg_and_die("adjtimex"); bb_perror_msg_and_die("adjtimex");
if (G.kernel_freq_drift != tmx.freq / 65536) {
G.kernel_freq_drift = tmx.freq / 65536;
VERB2 bb_error_msg("kernel clock drift: %ld ppm", G.kernel_freq_drift);
}
VERB3 { VERB3 {
bb_error_msg("adjtimex:%d freq:%ld offset:%ld constant:%ld status:0x%x", bb_error_msg("adjtimex:%d freq:%ld offset:%ld constant:%ld status:0x%x",
rc, tmx.freq, tmx.offset, tmx.constant, tmx.status); rc, tmx.freq, tmx.offset, tmx.constant, tmx.status);
#if 0
/* always gives the same output as above msg */
memset(&tmx, 0, sizeof(tmx)); memset(&tmx, 0, sizeof(tmx));
if (adjtimex(&tmx) < 0) if (adjtimex(&tmx) < 0)
bb_perror_msg_and_die("adjtimex"); bb_perror_msg_and_die("adjtimex");
VERB3 bb_error_msg("c adjtimex freq:%ld offset:%ld constant:%ld status:0x%x", VERB3 bb_error_msg("c adjtimex freq:%ld offset:%ld constant:%ld status:0x%x",
tmx.freq, tmx.offset, tmx.constant, tmx.status); tmx.freq, tmx.offset, tmx.constant, tmx.status);
#endif
} }
// #define STA_MODE 0x4000 /* mode (0 = PLL, 1 = FLL) (ro) */ - ? // #define STA_MODE 0x4000 /* mode (0 = PLL, 1 = FLL) (ro) */ - ?
// it appeared after a while: // it appeared after a while: