pktgen: remove ndelay() call
Daniel Turull reported inaccuracies in pktgen when using low packet
rates, because we call ndelay(val) with values bigger than 20000.
Instead of calling ndelay() for delays < 100us, we can instead loop
calling ktime_now() only.
Reported-by: Daniel Turull <daniel.turull@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index 6bbf008..0001c24 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -2145,9 +2145,12 @@
}
start_time = ktime_now();
- if (remaining < 100000)
- ndelay(remaining); /* really small just spin */
- else {
+ if (remaining < 100000) {
+ /* for small delays (<100us), just loop until limit is reached */
+ do {
+ end_time = ktime_now();
+ } while (ktime_lt(end_time, spin_until));
+ } else {
/* see do_nanosleep */
hrtimer_init_sleeper(&t, current);
do {
@@ -2162,8 +2165,8 @@
hrtimer_cancel(&t.timer);
} while (t.task && pkt_dev->running && !signal_pending(current));
__set_current_state(TASK_RUNNING);
+ end_time = ktime_now();
}
- end_time = ktime_now();
pkt_dev->idle_acc += ktime_to_ns(ktime_sub(end_time, start_time));
pkt_dev->next_tx = ktime_add_ns(spin_until, pkt_dev->delay);
