pktgen: spin using hrtimer
This changes how the pktgen thread spins/waits between
packets if delay is configured. It uses a high res timer to
wait for time to arrive.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index bede00b..3045dd1 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -131,6 +131,7 @@
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/capability.h>
+#include <linux/hrtimer.h>
#include <linux/freezer.h>
#include <linux/delay.h>
#include <linux/timer.h>
@@ -2086,33 +2087,40 @@
pkt_dev->nflows = 0;
}
-static inline s64 delta_ns(ktime_t a, ktime_t b)
-{
- return ktime_to_ns(ktime_sub(a, b));
-}
static void spin(struct pktgen_dev *pkt_dev, ktime_t spin_until)
{
- ktime_t start, now;
- s64 dt;
+ ktime_t start;
+ s32 remaining;
+ struct hrtimer_sleeper t;
- start = now = ktime_now();
+ hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+ hrtimer_set_expires(&t.timer, spin_until);
- while ((dt = delta_ns(spin_until, now)) > 0) {
- /* TODO: optimize sleeping behavior */
- if (dt > TICK_NSEC)
- schedule_timeout_interruptible(1);
- else if (dt > 100*NSEC_PER_USEC) {
- if (!pkt_dev->running)
- return;
- if (need_resched())
+ remaining = ktime_to_us(hrtimer_expires_remaining(&t.timer));
+ if (remaining <= 0)
+ return;
+
+ start = ktime_now();
+ if (remaining < 100)
+ udelay(remaining); /* really small just spin */
+ else {
+ /* see do_nanosleep */
+ hrtimer_init_sleeper(&t, current);
+ do {
+ set_current_state(TASK_INTERRUPTIBLE);
+ hrtimer_start_expires(&t.timer, HRTIMER_MODE_ABS);
+ if (!hrtimer_active(&t.timer))
+ t.task = NULL;
+
+ if (likely(t.task))
schedule();
- }
- now = ktime_now();
+ hrtimer_cancel(&t.timer);
+ } while (t.task && pkt_dev->running && !signal_pending(current));
+ __set_current_state(TASK_RUNNING);
}
-
- pkt_dev->idle_acc += ktime_to_ns(ktime_sub(now, start));
+ pkt_dev->idle_acc += ktime_to_ns(ktime_sub(ktime_now(), start));
}
static inline void set_pkt_overhead(struct pktgen_dev *pkt_dev)
@@ -3360,8 +3368,7 @@
int ret;
if (pkt_dev->delay) {
- if (ktime_lt(ktime_now(), pkt_dev->next_tx))
- spin(pkt_dev, pkt_dev->next_tx);
+ spin(pkt_dev, pkt_dev->next_tx);
/* This is max DELAY, this has special meaning of
* "never transmit"
