Improve netsend timing logic in various ways:
- Centralize time comparison. - Check clock resolution to make sure it has enough granularity to implement the desired wait interval. - Keep track of how many times the timing loop has to spin waiting for the next send time; report statistics. - Add commented out warning about deadlines being missed when spinning. - Improve statistics reporting generally to provide a more useful summary of sender condition after a run.
This commit is contained in:
parent
cd3ee173f9
commit
aa1cb3e183
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=135551
@ -61,21 +61,45 @@ timespec_add(struct timespec *tsa, struct timespec *tsb)
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}
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}
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static __inline int
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timespec_ge(struct timespec *a, struct timespec *b)
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{
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if (a->tv_sec > b->tv_sec)
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return (1);
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if (a->tv_sec < b->tv_sec)
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return (0);
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if (a->tv_nsec >= b->tv_nsec)
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return (1);
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return (0);
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}
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/*
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* Busy wait spinning until we reach (or slightly pass) the desired time.
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* Optionally return the current time as retrieved on the last time check
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* to the caller.
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* to the caller. Optionally also increment a counter provided by the
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* caller each time we loop.
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*/
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int
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wait_time(struct timespec ts, struct timespec *wakeup_ts)
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wait_time(struct timespec ts, struct timespec *wakeup_ts, long long *waited)
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{
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struct timespec curtime;
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curtime.tv_sec = 0;
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curtime.tv_nsec = 0;
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while (curtime.tv_sec < ts.tv_sec || curtime.tv_nsec < ts.tv_nsec) {
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if (clock_gettime(CLOCK_REALTIME, &curtime) < -1) {
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if (clock_gettime(CLOCK_REALTIME, &curtime) == -1) {
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perror("clock_gettime");
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return (-1);
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}
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#if 0
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if (timespec_ge(&curtime, &ts))
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printf("warning: wait_time missed deadline without spinning\n");
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#endif
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while (timespec_ge(&ts, &curtime)) {
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if (waited != NULL)
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(*waited)++;
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if (clock_gettime(CLOCK_REALTIME, &curtime) == -1) {
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perror("clock_gettime");
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return (-1);
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}
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@ -94,11 +118,23 @@ int
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timing_loop(int s, struct timespec interval, long duration, u_char *packet,
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u_int packet_len)
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{
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struct timespec starttime, tmptime;
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struct timespec nexttime, starttime, tmptime;
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long long waited;
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u_int32_t counter;
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long finishtime;
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int send_errors, send_calls;
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if (clock_gettime(CLOCK_REALTIME, &starttime) < -1) {
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if (clock_getres(CLOCK_REALTIME, &tmptime) == -1) {
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perror("clock_getres");
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return (-1);
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}
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if (timespec_ge(&tmptime, &interval))
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fprintf(stderr,
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"warning: interval less than resolution (%d.%09lu)\n",
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tmptime.tv_sec, tmptime.tv_nsec);
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if (clock_gettime(CLOCK_REALTIME, &starttime) == -1) {
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perror("clock_gettime");
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return (-1);
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}
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@ -106,14 +142,17 @@ timing_loop(int s, struct timespec interval, long duration, u_char *packet,
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tmptime.tv_nsec = 0;
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timespec_add(&starttime, &tmptime);
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starttime.tv_nsec = 0;
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if (wait_time(starttime, NULL) == -1)
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if (wait_time(starttime, NULL, NULL) == -1)
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return (-1);
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nexttime = starttime;
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finishtime = starttime.tv_sec + duration;
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send_errors = send_calls = 0;
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counter = 0;
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waited = 0;
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while (1) {
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timespec_add(&starttime, &interval);
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if (wait_time(starttime, &tmptime) == -1)
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timespec_add(&nexttime, &interval);
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if (wait_time(nexttime, &tmptime, &waited) == -1)
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return (-1);
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/*
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* We maintain and, if there's room, send a counter. Note
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@ -131,12 +170,34 @@ timing_loop(int s, struct timespec interval, long duration, u_char *packet,
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*((u_int32_t *)packet) = htonl(counter);
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counter++;
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}
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if (send(s, packet, packet_len, 0) < 0)
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if (send(s, packet, packet_len, 0) < 0) {
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perror("send");
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send_errors++;
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}
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send_calls++;
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if (duration != 0 && tmptime.tv_sec >= finishtime)
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return (0);
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goto done;
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}
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done:
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if (clock_gettime(CLOCK_REALTIME, &tmptime) == -1) {
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perror("clock_gettime");
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return (-1);
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}
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printf("\n");
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printf("start: %d.%09lu\n", starttime.tv_sec,
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starttime.tv_nsec);
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printf("finish: %d.%09lu\n", tmptime.tv_sec,
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tmptime.tv_nsec);
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printf("send calls: %d\n", send_calls);
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printf("send errors: %d\n", send_errors);
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printf("approx send rate: %ld\n", (send_calls - send_errors) /
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duration);
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printf("approx error rate: %ld\n", (send_errors / send_calls));
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printf("waited: %lld\n", waited);
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printf("approx wait rate: %lld\n", waited / send_calls);
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return (0);
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}
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@ -175,7 +236,8 @@ main(int argc, char *argv[])
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/*
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* Specify an arbitrary limit. It's exactly that, not selected by
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* any particular strategy.
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.* any particular strategy. '0' is a special value meaning "blast",
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* and avoids the cost of a timing loop.
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*/
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rate = strtoul(argv[4], &dummy, 10);
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if (rate < 1 || *dummy != '\0')
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@ -196,7 +258,10 @@ main(int argc, char *argv[])
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}
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bzero(packet, payloadsize);
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if (rate == 1) {
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if (rate == 0) {
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interval.tv_sec = 0;
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interval.tv_nsec = 0;
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} else if (rate == 1) {
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interval.tv_sec = 1;
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interval.tv_nsec = 0;
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} else {
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