217 lines
5.9 KiB
Diff
217 lines
5.9 KiB
Diff
|
Description: Add precision wait time option -p
|
||
|
|
Author: Anthony DeRobertis <asd@suespammers.org>
|
||
|
|
Bug-Debian: http://bugs.debian.org/183486
|
||
|
|
Reviewed-by: Craig Small <csmall@debian.org>
|
||
|
|
Index: b/watch.1
|
||
|
|
===================================================================
|
||
|
|
--- a/watch.1 2009-11-24 21:00:43.000000000 +1100
|
||
|
|
+++ b/watch.1 2009-11-24 21:00:46.000000000 +1100
|
||
|
|
@@ -4,7 +4,7 @@
|
||
|
|
.SH SYNOPSIS
|
||
|
|
.na
|
||
|
|
.B watch
|
||
|
|
-.RB [ \-bdehvtx ]
|
||
|
|
+.RB [ \-bdehpvtx ]
|
||
|
|
.RB [ \-n
|
||
|
|
.IR seconds ]
|
||
|
|
.RB [ \-\-beep ]
|
||
|
|
@@ -14,6 +14,7 @@
|
||
|
|
.RB [ \-\-help ]
|
||
|
|
.RB [ \-\-interval=\fIseconds\fP]
|
||
|
|
.RB [ \-\-no\-title ]
|
||
|
|
+.RB [ \-\-precise ]
|
||
|
|
.RB [ \-\-version ]
|
||
|
|
.I command
|
||
|
|
.SH DESCRIPTION
|
||
|
|
@@ -27,7 +28,24 @@
|
||
|
|
.B \-n
|
||
|
|
or
|
||
|
|
.B \-\-interval
|
||
|
|
-to specify a different interval.
|
||
|
|
+to specify a different interval. Normally, this interval is interpreted
|
||
|
|
+as the amout of time between the completion of one run of
|
||
|
|
+.I command
|
||
|
|
+and the beginning of the next run. However, with the
|
||
|
|
+.I \-p
|
||
|
|
+or
|
||
|
|
+.I \-\-precise
|
||
|
|
+option, you can make
|
||
|
|
+.BR watch
|
||
|
|
+attempt to run
|
||
|
|
+.I command
|
||
|
|
+every
|
||
|
|
+.I interval
|
||
|
|
+seconds. Try it with
|
||
|
|
+.B ntptime
|
||
|
|
+and notice how the fractional seconds stays
|
||
|
|
+(nearly) the same, as opposed to normal mode where they continuously
|
||
|
|
+increase.
|
||
|
|
.PP
|
||
|
|
The
|
||
|
|
.B \-d
|
||
|
|
@@ -97,11 +115,21 @@
|
||
|
|
.br
|
||
|
|
watch echo "'"'$$'"'"
|
||
|
|
.PP
|
||
|
|
+To see the effect of precision time keeping, try adding
|
||
|
|
+.I \-p
|
||
|
|
+to
|
||
|
|
+.IP
|
||
|
|
+watch \-n 10 sleep 1
|
||
|
|
+.PP
|
||
|
|
You can watch for your administrator to install the latest kernel with
|
||
|
|
.IP
|
||
|
|
watch uname \-r
|
||
|
|
.PP
|
||
|
|
-(Just kidding.)
|
||
|
|
+(Note that
|
||
|
|
+.I \-p
|
||
|
|
+isn't guaranteed to work across reboots, especially in the face of
|
||
|
|
+.B ntpdate
|
||
|
|
+or other bootup time-changing mechanisms)
|
||
|
|
.SH BUGS
|
||
|
|
Upon terminal resize, the screen will not be correctly repainted until the
|
||
|
|
next scheduled update. All
|
||
|
|
@@ -110,6 +138,22 @@
|
||
|
|
.PP
|
||
|
|
Non-printing characters are stripped from program output. Use "cat -v" as
|
||
|
|
part of the command pipeline if you want to see them.
|
||
|
|
+.PP
|
||
|
|
+.I \-\-precise
|
||
|
|
+mode doesn't yet have advanced temporal distortion technology to
|
||
|
|
+compensate for a
|
||
|
|
+.I command
|
||
|
|
+that takes more than
|
||
|
|
+.I interval
|
||
|
|
+seconds to execute.
|
||
|
|
+.B watch
|
||
|
|
+also can get into a state where it rapid-fires as many executions of
|
||
|
|
+.I command
|
||
|
|
+as it can to catch up from a previous executions running longer than
|
||
|
|
+.I interval
|
||
|
|
+(for example,
|
||
|
|
+.B netstat
|
||
|
|
+taking ages on a DNS lookup).
|
||
|
|
.SH AUTHORS
|
||
|
|
The original
|
||
|
|
.B watch
|
||
|
|
@@ -117,3 +161,7 @@
|
||
|
|
corrections by Francois Pinard. It was reworked and new features added by
|
||
|
|
Mike Coleman <mkc@acm.org> in 1999. The beep, exec, and error handling
|
||
|
|
features were added by Morty Abzug <morty@frakir.org> in 2008.
|
||
|
|
+On a not so dark and stormy morning
|
||
|
|
+in March of 2003, Anthony DeRobertis <asd@suespammers.org> got sick of
|
||
|
|
+his watches that should update every minute eventually updating many
|
||
|
|
+seconds after the minute started, and added microsecond precision.
|
||
|
|
Index: b/watch.c
|
||
|
|
===================================================================
|
||
|
|
--- a/watch.c 2009-11-24 21:00:43.000000000 +1100
|
||
|
|
+++ b/watch.c 2009-11-24 21:00:46.000000000 +1100
|
||
|
|
@@ -21,6 +21,7 @@
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <string.h>
|
||
|
|
#include <sys/ioctl.h>
|
||
|
|
+#include <sys/time.h>
|
||
|
|
#include <time.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
#include <termios.h>
|
||
|
|
@@ -39,13 +40,14 @@
|
||
|
|
{"beep", no_argument, 0, 'b'},
|
||
|
|
{"errexit", no_argument, 0, 'e'},
|
||
|
|
{"exec", no_argument, 0, 'x'},
|
||
|
|
+ {"precise", no_argument, 0, 'p'},
|
||
|
|
{"no-title", no_argument, 0, 't'},
|
||
|
|
{"version", no_argument, 0, 'v'},
|
||
|
|
{0, 0, 0, 0}
|
||
|
|
};
|
||
|
|
|
||
|
|
static char usage[] =
|
||
|
|
- "Usage: %s [-bdhntvx] [--beep] [--differences[=cumulative]] [--exec] [--help] [--interval=<n>] [--no-title] [--version] <command>\n";
|
||
|
|
+ "Usage: %s [-bdhnptvx] [--beep] [--differences[=cumulative]] [--exec] [--help] [--interval=<n>] [--no-title] [--version] <command>\n";
|
||
|
|
|
||
|
|
static char *progname;
|
||
|
|
|
||
|
|
@@ -54,6 +56,7 @@
|
||
|
|
static int screen_size_changed = 0;
|
||
|
|
static int first_screen = 1;
|
||
|
|
static int show_title = 2; // number of lines used, 2 or 0
|
||
|
|
+static int precise_timekeeping = 0;
|
||
|
|
|
||
|
|
#define min(x,y) ((x) > (y) ? (y) : (x))
|
||
|
|
|
||
|
|
@@ -138,6 +141,15 @@
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
+/* get current time in usec */
|
||
|
|
+typedef unsigned long long watch_usec_t;
|
||
|
|
+#define USECS_PER_SEC (1000000ull)
|
||
|
|
+watch_usec_t get_time_usec() {
|
||
|
|
+ struct timeval now;
|
||
|
|
+ gettimeofday(&now, NULL);
|
||
|
|
+ return USECS_PER_SEC*now.tv_sec + now.tv_usec;
|
||
|
|
+}
|
||
|
|
+
|
||
|
|
int
|
||
|
|
main(int argc, char *argv[])
|
||
|
|
{
|
||
|
|
@@ -152,6 +164,8 @@
|
||
|
|
char *command;
|
||
|
|
char **command_argv;
|
||
|
|
int command_length = 0; /* not including final \0 */
|
||
|
|
+ watch_usec_t next_loop; /* next loop time in us, used for precise time
|
||
|
|
+ keeping only */
|
||
|
|
int pipefd[2];
|
||
|
|
int status;
|
||
|
|
pid_t child;
|
||
|
|
@@ -159,7 +173,7 @@
|
||
|
|
setlocale(LC_ALL, "");
|
||
|
|
progname = argv[0];
|
||
|
|
|
||
|
|
- while ((optc = getopt_long(argc, argv, "+bed::hn:vtx", longopts, (int *) 0))
|
||
|
|
+ while ((optc = getopt_long(argc, argv, "+bed::hn:pvtx", longopts, (int *) 0))
|
||
|
|
!= EOF) {
|
||
|
|
switch (optc) {
|
||
|
|
case 'b':
|
||
|
|
@@ -194,6 +208,9 @@
|
||
|
|
interval = ~0u/1000000;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
+ case 'p':
|
||
|
|
+ precise_timekeeping = 1;
|
||
|
|
+ break;
|
||
|
|
case 'v':
|
||
|
|
option_version = 1;
|
||
|
|
break;
|
||
|
|
@@ -217,6 +234,7 @@
|
||
|
|
fputs(" -e, --errexit\t\t\t\texit watch if the command has a non-zero exit\n", stderr);
|
||
|
|
fputs(" -h, --help\t\t\t\tprint a summary of the options\n", stderr);
|
||
|
|
fputs(" -n, --interval=<seconds>\t\tseconds to wait between updates\n", stderr);
|
||
|
|
+ fputs(" -p, --precise\t\t\t\tprecise timing, ignore command run time\n", stderr);
|
||
|
|
fputs(" -v, --version\t\t\t\tprint the version number\n", stderr);
|
||
|
|
fputs(" -t, --no-title\t\t\tturns off showing the header\n", stderr);
|
||
|
|
fputs(" -x, --exec\t\t\t\tpass command to exec instead of sh\n", stderr);
|
||
|
|
@@ -256,6 +274,9 @@
|
||
|
|
noecho();
|
||
|
|
cbreak();
|
||
|
|
|
||
|
|
+ if (precise_timekeeping)
|
||
|
|
+ next_loop = get_time_usec();
|
||
|
|
+
|
||
|
|
for (;;) {
|
||
|
|
time_t t = time(NULL);
|
||
|
|
char *ts = ctime(&t);
|
||
|
|
@@ -400,6 +421,12 @@
|
||
|
|
|
||
|
|
first_screen = 0;
|
||
|
|
refresh();
|
||
|
|
+ if (precise_timekeeping) {
|
||
|
|
+ watch_usec_t cur_time = get_time_usec();
|
||
|
|
+ next_loop += USECS_PER_SEC*interval;
|
||
|
|
+ if (cur_time < next_loop)
|
||
|
|
+ usleep(next_loop - cur_time);
|
||
|
|
+ } else
|
||
|
|
usleep(interval * 1000000);
|
||
|
|
}
|
||
|
|
|