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Base poll adjustment on number of sourcestats samples

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Instead of following skew changes, adjust polling interval so that the
number of measurements used in the regression algorithm remains close to
a target value. It can be configured with a new polltarget option
(6 by default).
This commit is contained in:
Miroslav Lichvar
2010-10-13 16:49:28 +02:00
parent d9596334c3
commit 7a6ee1d729
12 changed files with 88 additions and 50 deletions
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81
ntp_core.c
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@@ -55,10 +55,6 @@ static LOG_FileID logfileid;
/* Day number of 1 Jan 1970 */
#define MJD_1970 40587
/* ================================================== */
#define ZONE_WIDTH 4
/* ================================================== */
/* Enumeration used for remembering the operating mode of one of the
sources */
@@ -110,6 +106,10 @@ struct NCR_Instance_Record {
int min_stratum; /* Increase stratum in received packets to the
minimum */
int poll_target; /* Target number of sourcestats samples */
double poll_score; /* Score of current local poll */
double max_delay; /* Maximum round-trip delay to the
peer that we can tolerate and still
use the sample for generating
@@ -163,8 +163,6 @@ struct NCR_Instance_Record {
SRC_Instance source;
int score;
int burst_good_samples_to_go;
int burst_total_samples_to_go;
@@ -215,7 +213,7 @@ void
NCR_Initialise(void)
{
logfileid = CNF_GetLogMeasurements() ? LOG_FileOpen("measurements",
" Date (UTC) Time IP Address L St 1234 ab 5678 LP RP SC Offset Peer del. Peer disp. Root del. Root disp.")
" Date (UTC) Time IP Address L St 1234 ab 5678 LP RP Score Offset Peer del. Peer disp. Root del. Root disp.")
: -1;
access_auth_table = ADF_CreateTable();
@@ -292,7 +290,8 @@ NCR_GetInstance(NTP_Remote_Address *remote_addr, NTP_Source_Type type, SourcePar
result->remote_orig.hi = 0;
result->remote_orig.lo = 0;
result->score = 0;
result->poll_target = params->poll_target;
result->poll_score = 0.0;
if (params->online) {
start_initial_timeout(result);
@@ -448,29 +447,28 @@ check_packet_auth(NTP_Packet *pkt, unsigned long keyid)
/* ================================================== */
static void
normalise_score(NCR_Instance inst)
adjust_poll(NCR_Instance inst, double adj)
{
inst->poll_score += adj;
while (inst->score >= ZONE_WIDTH) {
++inst->local_poll;
inst->score -= ZONE_WIDTH;
if (inst->poll_score >= 1.0) {
inst->local_poll += (int)inst->poll_score;
inst->poll_score -= (int)inst->poll_score;
}
while (inst->score < 0) {
if (inst->local_poll > 0) {
--inst->local_poll;
}
inst->score += ZONE_WIDTH;
if (inst->poll_score < 0.0) {
inst->local_poll += (int)(inst->poll_score - 1.0);
inst->poll_score -= (int)(inst->poll_score - 1.0);
}
/* Clamp polling interval to defined range */
if (inst->local_poll < inst->minpoll) {
inst->local_poll = inst->minpoll;
inst->score = 0;
inst->poll_score = 0;
} else if (inst->local_poll > inst->maxpoll) {
inst->local_poll = inst->maxpoll;
inst->score = ZONE_WIDTH - 1;
inst->poll_score = 1.0;
}
}
/* ================================================== */
@@ -652,13 +650,11 @@ transmit_timeout(void *arg)
if (SRC_IsSyncPeer(inst->source)) {
if (inst->tx_count >= 2) {
/* Implies we have missed at least one transmission */
inst->score -= 3;
normalise_score(inst);
adjust_poll(inst, -0.75);
}
} else {
if (inst->tx_count >= 2) {
inst->score += 1;
normalise_score(inst);
adjust_poll(inst, 0.25);
}
}
@@ -810,7 +806,7 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
int poll_to_use;
double delay_time = 0;
int requeue_transmit = 0;
int delta_score;
double poll_adj;
/* ==================== */
@@ -1089,31 +1085,22 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
temp>>=1;
} while (temp);
inst->local_poll -= shift;
inst->score = 0;
poll_adj = -shift - inst->poll_score + 0.5;
} else {
int samples = SRC_Samples(inst->source);
switch (SRC_LastSkewChange(inst->source)) {
case SRC_Skew_Decrease:
delta_score = 1;
break;
case SRC_Skew_Nochange:
delta_score = 0;
break;
case SRC_Skew_Increase:
delta_score = -2;
break;
default: /* Should not happen! */
delta_score = 0;
break;
}
/* Adjust polling interval so that the number of sourcestats samples
remains close to the target value */
poll_adj = ((double)samples / inst->poll_target - 1.0) / inst->poll_target;
inst->score += delta_score;
/* Use higher gain when decreasing the interval */
if (samples < inst->poll_target) {
poll_adj *= 2.0;
}
}
normalise_score(inst);
adjust_poll(inst, poll_adj);
}
/* Reduce polling rate if KoD RATE was received */
@@ -1253,7 +1240,7 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
/* Do measurement logging */
if (logfileid != -1) {
LOG_FileWrite(logfileid, "%s %-15s %1c %2d %1d%1d%1d%1d %1d%1d %1d%1d%1d%1d %2d %2d %2d %10.3e %10.3e %10.3e %10.3e %10.3e",
LOG_FileWrite(logfileid, "%s %-15s %1c %2d %1d%1d%1d%1d %1d%1d %1d%1d%1d%1d %2d %2d %4.2f %10.3e %10.3e %10.3e %10.3e %10.3e",
UTI_TimeToLogForm(sample_time.tv_sec),
UTI_IPToString(&inst->remote_addr.ip_addr),
sync_stats[pkt_leap],
@@ -1262,7 +1249,7 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
test4a, test4b,
test5, test6, test7, test8,
inst->local_poll, inst->remote_poll,
(inst->score),
inst->poll_score,
theta, delta, epsilon,
pkt_root_delay, pkt_root_dispersion);
}
@@ -1668,7 +1655,7 @@ NCR_TakeSourceOnline(NCR_Instance inst)
/* We are not already actively polling it */
LOG(LOGS_INFO, LOGF_NtpCore, "Source %s online", UTI_IPToString(&inst->remote_addr.ip_addr));
inst->local_poll = inst->minpoll;
inst->score = (ZONE_WIDTH >> 1);
inst->poll_score = 0.5;
inst->opmode = MD_ONLINE;
start_initial_timeout(inst);
}