[svn-commits] tzafrir: branch tzafrir/xpp_1.2 r1533 - /team/tzafrir/xpp_1.2/xpp/utils/

svn-commits at lists.digium.com svn-commits at lists.digium.com
Tue Oct 24 13:32:08 MST 2006


Author: tzafrir
Date: Tue Oct 24 15:32:07 2006
New Revision: 1533

URL: http://svn.digium.com/view/zaptel?rev=1533&view=rev
Log:
adj_clock (missing from previous commit) : sync system clock from Zaptel clock

Added:
    team/tzafrir/xpp_1.2/xpp/utils/adj_clock.8   (with props)
    team/tzafrir/xpp_1.2/xpp/utils/adj_clock.c   (with props)

Added: team/tzafrir/xpp_1.2/xpp/utils/adj_clock.8
URL: http://svn.digium.com/view/zaptel/team/tzafrir/xpp_1.2/xpp/utils/adj_clock.8?rev=1533&view=auto
==============================================================================
--- team/tzafrir/xpp_1.2/xpp/utils/adj_clock.8 (added)
+++ team/tzafrir/xpp_1.2/xpp/utils/adj_clock.8 Tue Oct 24 15:32:07 2006
@@ -1,0 +1,144 @@
+." $Id$
+.TH adj_clock 8 "2006-10-18" 
+.SH "NAME" 
+adj_clock \(em Synchronize system clock to zaptel clock
+.SH "SYNOPSIS" 
+.B adj_clock 
+.I [ -c
+.B count
+.I ] [ -i 
+.B interval
+.I ] [ -t 
+.B period
+.I ] [ -v ]
+
+.SH "DESCRIPTION" 
+.B adj_clock
+compares synchronizes the system clock from Zaptel's clock: in each cycle
+It will read 1024 * 
+.B interval
+ticks from a Zaptel pseudo channel, which should take exactly 
+.B interval
+seconds. It measures the time it did take, and uses 
+.I adjtimex(3)
+to fix the system clock accordingly.
+
+Note that NTP servers usually use adjtimex. You may get strange behaviour 
+if you have a NTP server (such as ntpd(8)) running on the system.
+
+Output is sent to both the standard error and to the syslog. Syslog 
+messages are with facility daemon.
+
+.SH OPTIONS
+.I -c
+.B count
+.RS
+Run just 
+.B count
+synchronization cycles. Default is to run forever.
+.RE
+
+.I -i 
+.B interval
+.RS
+Loop interval (in seconds). Optional, as program should provide a sane value.
+
+Small values allow faster synchronization when the system is quiet. Even 
+a value as low as 10 should work. However they are much more suspectable 
+to short interruptions. 
+
+.RE
+
+.I -t
+.B period
+.RS
+Set the synchronization tolerance priod (micro-seconds). The default
+is 100. Don't touch it unless you know what you're doing.
+.RE
+
+.I -v
+.RS
+Be more verbose: log status messages even when synchronized.
+.RE
+
+.SH FILES
+.B /dev/zap/pseudo
+.RS
+.RE
+The device file used to open a "pseudo" channel (a channels that
+constantly streams voice and is synchronized by the master Zaptel
+device).
+
+.SH SYNCHRONIZATION
+Some more technical details. This explains the strange numbers the
+program prints.
+
+In each cycle
+.B adj_clock 
+measures 
+.B interval
+seconds using Zaptel ticks. It then compares that to the system time
+from gettimeofday(2). It then calls adjtimex(2) to slightly change the 
+rate of the system clock. It uses two parameters: 
+.B ticks, 
+which is a more
+coarse one (1 tick will give roughly a change of rate of 9 seconds per
+day) and 
+.I frequency, 
+which allows much finer settings.
+
+The program tries to set what it can by ticks, and the rest through
+frequency. It considers itself "synchronized" when the rate difference
+is small enough so 
+.I (a)
+It does not have to use ticks anymore. And
+.I (b) 
+The rest of the interval to change is smaller than the tolerance period
+(100 micro-seconds, by default).
+
+The meaning of the parameters it prints is, thus:
+
+.I interval
+.RS
+The current interval parameter (seconds).
+.RE
+
+.I diff_tick
+.RS
+The number of ticks it tries to set through adjtimex(2). 
+Anything different than 0 means we're still way off mark.
+.RE
+
+.I diff_usec
+.RS
+The time difference (micro-seconds) that we need to overcome in the 
+first place. This is the difference between the system clock and the
+measured zaptel clock.
+.RE
+
+.I usec_left
+.RS
+How much of this difference (microseconds) we still need to adjust
+after using ticks. This should be low enough (less than the tolerance
+period).
+.RE
+
+.SH SIGNALS
+.B adj_clock
+is so far an interactive program, and thus killed by SIGHUP. SIGUSR is 
+used to increase verbosity level and SIGUSR2 is used to reset verbosity
+level to 0. When SIGUSR1 is recieved a status message will also be sent 
+to the logs.
+
+.SH SEE ALSO 
+ztcfg(8), zttest(8), adjtimex(2), gettimeofday(2), adjtimex(8)
+
+.SH AUTHOR 
+
+This manual page was written by Tzafrir Cohen <tzafrir.cohen at xorcom.com> 
+Permission is granted to copy, distribute and/or modify this document under 
+the terms of the GNU General Public License, Version 2 any  
+later version published by the Free Software Foundation. 
+ 
+On Debian systems, the complete text of the GNU General Public 
+License can be found in /usr/share/common-licenses/GPL. 

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Added: team/tzafrir/xpp_1.2/xpp/utils/adj_clock.c
URL: http://svn.digium.com/view/zaptel/team/tzafrir/xpp_1.2/xpp/utils/adj_clock.c?rev=1533&view=auto
==============================================================================
--- team/tzafrir/xpp_1.2/xpp/utils/adj_clock.c (added)
+++ team/tzafrir/xpp_1.2/xpp/utils/adj_clock.c Tue Oct 24 15:32:07 2006
@@ -1,0 +1,228 @@
+/*
+ * Written by Tzafrir Cohen <tzafrir.cohen at xorcom.com>
+ * Copyright (C) 2006, Xorcom
+ *
+ * Derived from zttest.c
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+#include <sys/timex.h>
+#include <linux/param.h>
+#include <syslog.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/time.h>
+#include <sys/signal.h>
+#include <math.h>
+
+static const char *rcsid = "$Id$";
+
+#define FREQ_PER_TICK		(64*1024)
+#define USEC_PER_ZAP_TICK	1000	/* Zaptel tick in usec */
+#define	USER_HZ			100
+#define	SYNC_TOLERANCE		100
+#define DEFAULT_INTERVAL	 60
+
+static const char	*program;
+static int		synced_time; /* time (seconds) we are so far synced */
+static int 		verbose = 0;
+static int		sync_tolerance = 100;
+
+void usage() {
+	fprintf(stderr, "%s: synchronize system clock from zaptel clock.\n"
+		"Version: %s\n"
+		"\n"
+		"Usage: %s [ -c COUNT ] [-i INTERVAL] [ -t PERIOD ] [-v]\n"
+		"       %s -h\n"
+		"\n"
+		"Options:\n"
+		"     -c   only run COUNT cycles of synchronization (default: forever).\n"
+		"     -i   set cycle Interval to INTERVAL (in seconds. Default: %d).\n"
+		"     -t   sync tolerance to PERIOD (in usec. Default: %d). For debugging.\n"
+		"     -v   Be more Verbose\n"
+		"     -h   Print this Help text and exit.\n"
+		"", program, rcsid, program, program, DEFAULT_INTERVAL, 
+		sync_tolerance);
+}
+
+/* based on zttest.c */
+
+/*
+ * Print a message to the log according to the value of synced_time
+ *
+ * All parameters are for the "Not Synced" warning message. 
+ * TODO: Find a better way.
+ */
+void status_message(void) {
+	if (synced_time == 0)
+		syslog(LOG_NOTICE, "Not Synced.\n");
+	else
+		syslog(LOG_INFO, "Good Sync for %d seconds\n", synced_time);
+
+	return;
+}
+
+/*
+ * interval: period, in seconds
+ * diff_usec: Current offset, in micro-seconds.
+ */
+int clock_sync(int interval, int diff_usec)
+{
+	struct timex	cur_time  = {.modes=0}; /* just query */
+	int		diff_tick;	/* Difference in adjtimex ticks */
+	int		req_tick;	/* Required adjtimex tick value */
+	long long	diff_freq;
+	long long	req_freq;
+	int		usec_left;	/* Usec adjusted by frequency	*/
+	int		ret;
+
+	ret = adjtimex(&cur_time);
+
+	diff_tick = diff_usec / (interval * USER_HZ);
+	usec_left = diff_usec - diff_tick * (interval * USER_HZ);
+	diff_freq = usec_left * FREQ_PER_TICK / interval;
+
+	req_tick = cur_time.tick - diff_tick;
+	req_freq = cur_time.freq - diff_freq;
+
+	if(!diff_tick && abs(usec_left) < sync_tolerance)
+		synced_time += interval;
+	else 
+		synced_time = 0;
+	status_message();
+	if (verbose || !synced_time)
+		syslog(LOG_INFO, "interval: %d, diff_tick: %d, diff_usec: %d, usec_left: %d.\n",
+			interval, diff_tick, diff_usec, usec_left);
+
+	/* set the clock rate */
+	cur_time.freq = req_freq;
+	cur_time.tick = req_tick;
+	cur_time.modes = ADJ_TICK | ADJ_FREQUENCY;
+	ret = adjtimex(&cur_time);
+	if (ret < 0)
+		syslog(LOG_ERR, "Adjtimex failed to set frequency. New frequency: %lld. Error: %d (%s)\n",
+				req_freq, errno, strerror(errno));
+	return 0;
+}
+
+static int pass = 0;
+
+void hup_handler(int sig)
+{
+	if (verbose > 0) {
+		syslog(LOG_INFO, "--- Results after %d passes ---\n", pass);
+		status_message();
+	}
+	closelog();
+	exit(0);
+}
+
+void sigusr1_handler(int sig) {
+	verbose++;
+	syslog(LOG_INFO, "Increased verbosity to %d (increase: SIGUSR1, reset: SIGUSR2).\n", verbose);
+	status_message();
+}
+
+void sigusr2_handler(int sig) {
+	verbose = 0;
+	syslog(LOG_INFO, "Set verbosity to 0 (increase: SIGUSR1, reset: SIGUSR2).\n");
+}
+
+void sync_cycle(int fd, int interval)
+{
+	char		buf[1024]; /* TODO: why 1024 and not 1000? */
+	struct timeval	start;
+	struct timeval	end;
+	long long	usec;
+	int		count = 0;
+	int		i;
+	int		res;
+
+	gettimeofday(&start, NULL);
+	for (i=0; i < interval*8; i++) {
+		res = read(fd, buf, sizeof(buf));
+		if (res < 0) {
+			syslog(LOG_ERR, "Failed to read from pseudo interface: %s\n", strerror(errno));
+			exit(1);
+		}
+		count += res/8;
+	}
+	gettimeofday(&end, NULL);
+
+	/* time difference in microseconds: */
+	usec = (end.tv_sec - start.tv_sec) * 1000000;
+	usec += end.tv_usec - start.tv_usec;
+
+	clock_sync(interval, usec - (count * USEC_PER_ZAP_TICK));
+
+	pass++;
+}
+
+int main(int argc, char *argv[])
+{
+	int fd;
+	int opt;
+	int interval = DEFAULT_INTERVAL;
+	int cycles_to_run = 0;
+	int i;
+
+	program = argv[0];
+	while((opt = getopt(argc, argv, "c:hi:t:v")) != -1) {
+		switch (opt) {
+			case 'h': usage(); exit(0); break;
+			case 'c': cycles_to_run = atoi(optarg); break;
+			case 'i': interval = atoi(optarg); break; /* number of seconds */
+			case 't': sync_tolerance = atoi(optarg); break; /* usec */
+			case 'v': verbose++; break;
+			default: 
+				  fprintf(stderr, "%s: Unknown option: %c. Aborting\n", argv[0], opt);
+				  usage();
+				  exit(1);
+		}
+	}
+
+	openlog(program, LOG_PERROR | LOG_PID, LOG_DAEMON);
+	fd = open("/dev/zap/pseudo", O_RDWR);
+	if (fd < 0) {
+		fprintf(stderr, "Unable to open zap interface: %s\n", strerror(errno));
+		exit(1);
+	}
+	if (verbose >=1)
+		syslog(LOG_INFO, "Opened pseudo zap interface, measuring accuracy...\n");
+
+	signal(SIGHUP, hup_handler);
+	signal(SIGINT, hup_handler);
+	signal(SIGUSR1, sigusr1_handler);
+	signal(SIGUSR2, sigusr2_handler);
+	
+	if (cycles_to_run > 0) {
+		for(i=0; i<cycles_to_run; i++) {
+			sync_cycle(fd, interval);
+		}
+		hup_handler(0); /* exit */;
+	}
+	
+	/* else (option -c not provided): run forever. */
+	for(;;) {
+		sync_cycle(fd, interval);
+	}
+}

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