pktgen: better scheduler friendliness
Previous update did not resched in inner loop causing watchdogs.
Rewrite inner loop to:
* account for delays better with less clock calls
* more accurate timing of delay:
- only delay if packet was successfully sent
- if delay is 100ns and it takes 10ns to build packet then
account for that
* use wait_event_interruptible_timeout rather than open coding it.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Stephen Hemminger
David S. Miller
parent
6b80d6a6b4
commit
ef87979c27
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@ -2104,7 +2104,7 @@ static void pktgen_setup_inject(struct pktgen_dev *pkt_dev)
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static void spin(struct pktgen_dev *pkt_dev, ktime_t spin_until)
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{
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ktime_t start;
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ktime_t start_time, end_time;
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s32 remaining;
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struct hrtimer_sleeper t;
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@ -2115,7 +2115,7 @@ static void spin(struct pktgen_dev *pkt_dev, ktime_t spin_until)
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if (remaining <= 0)
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return;
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start = ktime_now();
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start_time = ktime_now();
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if (remaining < 100)
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udelay(remaining); /* really small just spin */
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else {
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@ -2134,7 +2134,10 @@ static void spin(struct pktgen_dev *pkt_dev, ktime_t spin_until)
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} while (t.task && pkt_dev->running && !signal_pending(current));
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__set_current_state(TASK_RUNNING);
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}
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pkt_dev->idle_acc += ktime_to_ns(ktime_sub(ktime_now(), start));
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end_time = ktime_now();
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pkt_dev->idle_acc += ktime_to_ns(ktime_sub(end_time, start_time));
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pkt_dev->next_tx = ktime_add_ns(end_time, pkt_dev->delay);
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}
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static inline void set_pkt_overhead(struct pktgen_dev *pkt_dev)
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@ -3364,18 +3367,28 @@ static void pktgen_rem_thread(struct pktgen_thread *t)
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mutex_unlock(&pktgen_thread_lock);
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}
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static void idle(struct pktgen_dev *pkt_dev)
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static void pktgen_resched(struct pktgen_dev *pkt_dev)
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{
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ktime_t idle_start = ktime_now();
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if (need_resched())
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schedule();
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else
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cpu_relax();
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pkt_dev->idle_acc += ktime_to_ns(ktime_sub(ktime_now(), idle_start));
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}
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static void pktgen_wait_for_skb(struct pktgen_dev *pkt_dev)
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{
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ktime_t idle_start = ktime_now();
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while (atomic_read(&(pkt_dev->skb->users)) != 1) {
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if (signal_pending(current))
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break;
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if (need_resched())
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pktgen_resched(pkt_dev);
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else
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cpu_relax();
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}
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pkt_dev->idle_acc += ktime_to_ns(ktime_sub(ktime_now(), idle_start));
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}
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static void pktgen_xmit(struct pktgen_dev *pkt_dev)
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{
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@ -3386,36 +3399,21 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
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u16 queue_map;
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int ret;
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if (pkt_dev->delay) {
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spin(pkt_dev, pkt_dev->next_tx);
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/* This is max DELAY, this has special meaning of
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* "never transmit"
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*/
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if (pkt_dev->delay == ULLONG_MAX) {
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pkt_dev->next_tx = ktime_add_ns(ktime_now(), ULONG_MAX);
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return;
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}
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}
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if (!pkt_dev->skb) {
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set_cur_queue_map(pkt_dev);
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queue_map = pkt_dev->cur_queue_map;
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} else {
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queue_map = skb_get_queue_mapping(pkt_dev->skb);
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}
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txq = netdev_get_tx_queue(odev, queue_map);
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/* Did we saturate the queue already? */
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if (netif_tx_queue_stopped(txq) || netif_tx_queue_frozen(txq)) {
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/* If device is down, then all queues are permnantly frozen */
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if (netif_running(odev))
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idle(pkt_dev);
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else
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/* If device is offline, then don't send */
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if (unlikely(!netif_running(odev) || !netif_carrier_ok(odev))) {
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pktgen_stop_device(pkt_dev);
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return;
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}
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/* This is max DELAY, this has special meaning of
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* "never transmit"
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*/
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if (unlikely(pkt_dev->delay == ULLONG_MAX)) {
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pkt_dev->next_tx = ktime_add_ns(ktime_now(), ULONG_MAX);
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return;
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}
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/* If no skb or clone count exhausted then get new one */
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if (!pkt_dev->skb || (pkt_dev->last_ok &&
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++pkt_dev->clone_count >= pkt_dev->clone_skb)) {
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/* build a new pkt */
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@ -3434,18 +3432,20 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
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pkt_dev->clone_count = 0; /* reset counter */
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}
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/* fill_packet() might have changed the queue */
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if (pkt_dev->delay && pkt_dev->last_ok)
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spin(pkt_dev, pkt_dev->next_tx);
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queue_map = skb_get_queue_mapping(pkt_dev->skb);
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txq = netdev_get_tx_queue(odev, queue_map);
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__netif_tx_lock_bh(txq);
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if (unlikely(netif_tx_queue_stopped(txq) || netif_tx_queue_frozen(txq)))
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pkt_dev->last_ok = 0;
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else {
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atomic_inc(&(pkt_dev->skb->users));
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retry_now:
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if (unlikely(netif_tx_queue_stopped(txq) || netif_tx_queue_frozen(txq)))
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ret = NETDEV_TX_BUSY;
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else
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ret = (*xmit)(pkt_dev->skb, odev);
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switch (ret) {
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case NETDEV_TX_OK:
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txq_trans_update(txq);
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@ -3454,34 +3454,23 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
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pkt_dev->seq_num++;
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pkt_dev->tx_bytes += pkt_dev->cur_pkt_size;
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break;
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case NETDEV_TX_LOCKED:
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cpu_relax();
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goto retry_now;
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default: /* Drivers are not supposed to return other values! */
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if (net_ratelimit())
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pr_info("pktgen: %s xmit error: %d\n",
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odev->name, ret);
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pkt_dev->errors++;
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/* fallthru */
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case NETDEV_TX_LOCKED:
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case NETDEV_TX_BUSY:
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/* Retry it next time */
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atomic_dec(&(pkt_dev->skb->users));
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pkt_dev->last_ok = 0;
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}
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if (pkt_dev->delay)
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pkt_dev->next_tx = ktime_add_ns(ktime_now(),
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pkt_dev->delay);
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}
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__netif_tx_unlock_bh(txq);
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/* If pkt_dev->count is zero, then run forever */
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if ((pkt_dev->count != 0) && (pkt_dev->sofar >= pkt_dev->count)) {
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while (atomic_read(&(pkt_dev->skb->users)) != 1) {
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if (signal_pending(current))
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break;
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idle(pkt_dev);
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}
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pktgen_wait_for_skb(pkt_dev);
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/* Done with this */
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pktgen_stop_device(pkt_dev);
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@ -3514,20 +3503,24 @@ static int pktgen_thread_worker(void *arg)
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while (!kthread_should_stop()) {
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pkt_dev = next_to_run(t);
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if (!pkt_dev &&
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(t->control & (T_STOP | T_RUN | T_REMDEVALL | T_REMDEV))
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== 0) {
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prepare_to_wait(&(t->queue), &wait,
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TASK_INTERRUPTIBLE);
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schedule_timeout(HZ / 10);
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finish_wait(&(t->queue), &wait);
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if (unlikely(!pkt_dev && t->control == 0)) {
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wait_event_interruptible_timeout(t->queue,
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t->control != 0,
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HZ/10);
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continue;
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}
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__set_current_state(TASK_RUNNING);
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if (pkt_dev)
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if (likely(pkt_dev)) {
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pktgen_xmit(pkt_dev);
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if (need_resched())
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pktgen_resched(pkt_dev);
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else
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cpu_relax();
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}
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if (t->control & T_STOP) {
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pktgen_stop(t);
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t->control &= ~(T_STOP);
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