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Commit 2bc481cf authored by Stephen Hemminger's avatar Stephen Hemminger Committed by David S. Miller
Browse files

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: default avatarStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent fd29cf72

kernel/hrtimer.c

+2 −0
Original line number Diff line number Diff line
@@ -485,6 +485,7 @@ void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id, 
	debug_object_init_on_stack(timer, &hrtimer_debug_descr);

	__hrtimer_init(timer, clock_id, mode);

}

EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);



void destroy_hrtimer_on_stack(struct hrtimer *timer)

{
@@ -1477,6 +1478,7 @@ void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task) 
	sl->timer.function = hrtimer_wakeup;

	sl->task = task;

}

EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);



static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)

{

net/core/pktgen.c

+28 −21
Original line number Diff line number Diff line
@@ -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 @@ static void pktgen_setup_inject(struct pktgen_dev *pkt_dev) 
	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)

	remaining = ktime_to_us(hrtimer_expires_remaining(&t.timer));

	if (remaining <= 0)

		return;

			if (need_resched())



	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)
@@ -3360,7 +3368,6 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) 
	int ret;



	if (pkt_dev->delay) {

		if (ktime_lt(ktime_now(), pkt_dev->next_tx))

		spin(pkt_dev, pkt_dev->next_tx);



		/* This is max DELAY, this has special meaning of