selftests: txtimestamp: print statistics for timestamp events.

Statistics on timestamps is useful to quantify average and tail latency.

Print timestamp statistics in count/avg/min/max format.

Signed-off-by: Jian Yang <jianyang@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/tools/testing/selftests/networking/timestamping/txtimestamp.c b/tools/testing/selftests/networking/timestamping/txtimestamp.c
index f915f24..011b0da 100644 (file)
--- a/tools/testing/selftests/networking/timestamping/txtimestamp.c
+++ b/tools/testing/selftests/networking/timestamping/txtimestamp.c
@@ -84,6 +84,17 @@ static struct timespec ts_usr;
 static int saved_tskey = -1;
 static int saved_tskey_type = -1;
 
+struct timing_event {
+       int64_t min;
+       int64_t max;
+       int64_t total;
+       int count;
+};
+
+static struct timing_event usr_enq;
+static struct timing_event usr_snd;
+static struct timing_event usr_ack;
+
 static bool test_failed;
 
 static int64_t timespec_to_ns64(struct timespec *ts)
@@ -96,6 +107,27 @@ static int64_t timespec_to_us64(struct timespec *ts)
        return ts->tv_sec * USEC_PER_SEC + ts->tv_nsec / NSEC_PER_USEC;
 }
 
+static void init_timing_event(struct timing_event *te)
+{
+       te->min = INT64_MAX;
+       te->max = 0;
+       te->total = 0;
+       te->count = 0;
+}
+
+static void add_timing_event(struct timing_event *te,
+               struct timespec *t_start, struct timespec *t_end)
+{
+       int64_t ts_delta = timespec_to_ns64(t_end) - timespec_to_ns64(t_start);
+
+       te->count++;
+       if (ts_delta < te->min)
+               te->min = ts_delta;
+       if (ts_delta > te->max)
+               te->max = ts_delta;
+       te->total += ts_delta;
+}
+
 static void validate_key(int tskey, int tstype)
 {
        int stepsize;
@@ -187,14 +219,17 @@ static void print_timestamp(struct scm_timestamping *tss, int tstype,
        case SCM_TSTAMP_SCHED:
                tsname = "  ENQ";
                validate_timestamp(&tss->ts[0], 0);
+               add_timing_event(&usr_enq, &ts_usr, &tss->ts[0]);
                break;
        case SCM_TSTAMP_SND:
                tsname = "  SND";
                validate_timestamp(&tss->ts[0], cfg_delay_snd);
+               add_timing_event(&usr_snd, &ts_usr, &tss->ts[0]);
                break;
        case SCM_TSTAMP_ACK:
                tsname = "  ACK";
                validate_timestamp(&tss->ts[0], cfg_delay_ack);
+               add_timing_event(&usr_ack, &ts_usr, &tss->ts[0]);
                break;
        default:
                error(1, 0, "unknown timestamp type: %u",
@@ -203,6 +238,21 @@ static void print_timestamp(struct scm_timestamping *tss, int tstype,
        __print_timestamp(tsname, &tss->ts[0], tskey, payload_len);
 }
 
+static void print_timing_event(char *name, struct timing_event *te)
+{
+       if (!te->count)
+               return;
+
+       fprintf(stderr, "    %s: count=%d", name, te->count);
+       fprintf(stderr, ", avg=");
+       __print_ts_delta_formatted((int64_t)(te->total / te->count));
+       fprintf(stderr, ", min=");
+       __print_ts_delta_formatted(te->min);
+       fprintf(stderr, ", max=");
+       __print_ts_delta_formatted(te->max);
+       fprintf(stderr, "\n");
+}
+
 /* TODO: convert to check_and_print payload once API is stable */
 static void print_payload(char *data, int len)
 {
@@ -436,6 +486,10 @@ static void do_test(int family, unsigned int report_opt)
        char *buf;
        int fd, i, val = 1, total_len, epfd = 0;
 
+       init_timing_event(&usr_enq);
+       init_timing_event(&usr_snd);
+       init_timing_event(&usr_ack);
+
        total_len = cfg_payload_len;
        if (cfg_use_pf_packet || cfg_proto == SOCK_RAW) {
                total_len += sizeof(struct udphdr);
@@ -595,6 +649,10 @@ static void do_test(int family, unsigned int report_opt)
                while (!recv_errmsg(fd)) {}
        }
 
+       print_timing_event("USR-ENQ", &usr_enq);
+       print_timing_event("USR-SND", &usr_snd);
+       print_timing_event("USR-ACK", &usr_ack);
+
        if (close(fd))
                error(1, errno, "close");