search for: netif_xmit_stop

...gt; if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) { > netif_start_subqueue(dev, qnum); > virtqueue_disable_cb(sq->vq); > @@ -1560,7 +1566,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) > } > } > > - if (kick || netif_xmit_stopped(txq)) { > + if (use_napi) > + kick = __netdev_tx_sent_queue(txq, bytes, more); > + else > + kick = !more || netif_xmit_stopped(txq); > + > + if (kick) { > if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) { > u64_stats_update_begin(&...

...gt; if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) { > netif_start_subqueue(dev, qnum); > virtqueue_disable_cb(sq->vq); > @@ -1560,7 +1566,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) > } > } > > - if (kick || netif_xmit_stopped(txq)) { > + if (use_napi) > + kick = __netdev_tx_sent_queue(txq, bytes, more); > + else > + kick = !more || netif_xmit_stopped(txq); > + > + if (kick) { > if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) { > u64_stats_update_begin(&...

...MAX_SKB_FRAGS) { >>> netif_start_subqueue(dev, qnum); >>> virtqueue_disable_cb(sq->vq); >>> @@ -1560,7 +1566,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) >>> } >>> } >>> - if (kick || netif_xmit_stopped(txq)) { >>> + if (use_napi) >>> + kick = __netdev_tx_sent_queue(txq, bytes, more); >>> + else >>> + kick = !more || netif_xmit_stopped(txq); >>> + >>> + if (kick) { >>> if (virtqueue_kick_prepare(sq->vq) && virtqueu...

...MAX_SKB_FRAGS) { >>> netif_start_subqueue(dev, qnum); >>> virtqueue_disable_cb(sq->vq); >>> @@ -1560,7 +1566,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) >>> } >>> } >>> - if (kick || netif_xmit_stopped(txq)) { >>> + if (use_napi) >>> + kick = __netdev_tx_sent_queue(txq, bytes, more); >>> + else >>> + kick = !more || netif_xmit_stopped(txq); >>> + >>> + if (kick) { >>> if (virtqueue_kick_prepare(sq->vq) && virtqueu...

Now that we have brought the virtio overhead way down with a fast packed ring implementation, we seem to be actually observing TCP drops indicative of bufferbloat. So let's try to enable TSQ. Note: it isn't clear that the default pacing is great for the virt usecase. It's worth trying to play with sk_pacing_shift_update to see what happens. For this reason, and for a more important

...!skb->xmit_more; /* Free up any pending old buffers before queueing new ones. */ free_old_xmit_skbs(sq); @@ -956,7 +958,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) } } - if (__netif_subqueue_stopped(dev, qnum) || !skb->xmit_more) + if (kick || netif_xmit_stopped(txq)) virtqueue_kick(sq->vq); return NETDEV_TX_OK; -- MST

...!skb->xmit_more; /* Free up any pending old buffers before queueing new ones. */ free_old_xmit_skbs(sq); @@ -956,7 +958,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) } } - if (__netif_subqueue_stopped(dev, qnum) || !skb->xmit_more) + if (kick || netif_xmit_stopped(txq)) virtqueue_kick(sq->vq); return NETDEV_TX_OK; -- MST

...i = netdev_priv(dev); > + u32 i; > + > + /* find the stopped queue the same way dev_watchdog() does */ not really - the watchdog actually looks at trans_start. > + for (i = 0; i < vi->curr_queue_pairs; i++) { > + struct send_queue *sq = &vi->sq[i]; > + > + if (!netif_xmit_stopped(netdev_get_tx_queue(dev, i))) > + continue; > + > + u64_stats_update_begin(&sq->stats.syncp); > + sq->stats.tx_timeouts++; > + u64_stats_update_end(&sq->stats.syncp); > + > + netdev_warn(dev, "TX timeout on send queue: %d, sq: %s, vq: %d, name: %s...

...i = netdev_priv(dev); > + u32 i; > + > + /* find the stopped queue the same way dev_watchdog() does */ not really - the watchdog actually looks at trans_start. > + for (i = 0; i < vi->curr_queue_pairs; i++) { > + struct send_queue *sq = &vi->sq[i]; > + > + if (!netif_xmit_stopped(netdev_get_tx_queue(dev, i))) > + continue; > + > + u64_stats_update_begin(&sq->stats.syncp); > + sq->stats.tx_timeouts++; > + u64_stats_update_end(&sq->stats.syncp); > + > + netdev_warn(dev, "TX timeout on send queue: %d, sq: %s, vq: %d, name: %s...

...MAX_SKB_FRAGS) { >>> netif_start_subqueue(dev, qnum); >>> virtqueue_disable_cb(sq->vq); >>> @@ -1560,7 +1566,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) >>> } >>> } >>> - if (kick || netif_xmit_stopped(txq)) { >>> + if (use_napi) >>> + kick = __netdev_tx_sent_queue(txq, bytes, more); >>> + else >>> + kick = !more || netif_xmit_stopped(txq); >>> + >>> + if (kick) { >>> if (virtqueue_kick_prepare(sq->vq) && virtqueu...

...MAX_SKB_FRAGS) { >>> netif_start_subqueue(dev, qnum); >>> virtqueue_disable_cb(sq->vq); >>> @@ -1560,7 +1566,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) >>> } >>> } >>> - if (kick || netif_xmit_stopped(txq)) { >>> + if (use_napi) >>> + kick = __netdev_tx_sent_queue(txq, bytes, more); >>> + else >>> + kick = !more || netif_xmit_stopped(txq); >>> + >>> + if (kick) { >>> if (virtqueue_kick_prepare(sq->vq) && virtqueu...

...sq); + free_old_xmit_skbs(sq, txq, false); if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) { netif_start_subqueue(dev, qnum); virtqueue_disable_cb(sq->vq); @@ -1560,7 +1566,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) } } - if (kick || netif_xmit_stopped(txq)) { + if (use_napi) + kick = __netdev_tx_sent_queue(txq, bytes, more); + else + kick = !more || netif_xmit_stopped(txq); + + if (kick) { if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) { u64_stats_update_begin(&sq->stats.syncp); sq->stats....

...start_subqueue(dev, qnum); >>>>> virtqueue_disable_cb(sq->vq); >>>>> @@ -1560,7 +1566,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) >>>>> } >>>>> } >>>>> - if (kick || netif_xmit_stopped(txq)) { >>>>> + if (use_napi) >>>>> + kick = __netdev_tx_sent_queue(txq, bytes, more); >>>>> + else >>>>> + kick = !more || netif_xmit_stopped(txq); >>>>> + >>>>> + if (kick) { >>>>>...

...start_subqueue(dev, qnum); >>>>> virtqueue_disable_cb(sq->vq); >>>>> @@ -1560,7 +1566,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) >>>>> } >>>>> } >>>>> - if (kick || netif_xmit_stopped(txq)) { >>>>> + if (use_napi) >>>>> + kick = __netdev_tx_sent_queue(txq, bytes, more); >>>>> + else >>>>> + kick = !more || netif_xmit_stopped(txq); >>>>> + >>>>> + if (kick) { >>>>>...

...->num_free >= 2+MAX_SKB_FRAGS) { > > netif_start_subqueue(dev, qnum); > > virtqueue_disable_cb(sq->vq); > > @@ -1560,7 +1566,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) > > } > > } > > - if (kick || netif_xmit_stopped(txq)) { > > + if (use_napi) > > + kick = __netdev_tx_sent_queue(txq, bytes, more); > > + else > > + kick = !more || netif_xmit_stopped(txq); > > + > > + if (kick) { > > if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) {...

...->num_free >= 2+MAX_SKB_FRAGS) { > > netif_start_subqueue(dev, qnum); > > virtqueue_disable_cb(sq->vq); > > @@ -1560,7 +1566,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) > > } > > } > > - if (kick || netif_xmit_stopped(txq)) { > > + if (use_napi) > > + kick = __netdev_tx_sent_queue(txq, bytes, more); > > + else > > + kick = !more || netif_xmit_stopped(txq); > > + > > + if (kick) { > > if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) {...

...->num_free >= 2+MAX_SKB_FRAGS) { > > netif_start_subqueue(dev, qnum); > > virtqueue_disable_cb(sq->vq); > > @@ -1560,7 +1566,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) > > } > > } > > - if (kick || netif_xmit_stopped(txq)) { > > + if (use_napi) > > + kick = __netdev_tx_sent_queue(txq, bytes, more); > > + else > > + kick = !more || netif_xmit_stopped(txq); > > + > > + if (kick) { > > if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) {...

...netif_start_subqueue(dev, qnum); > > > > virtqueue_disable_cb(sq->vq); > > > > @@ -1560,7 +1566,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) > > > > } > > > > } > > > > - if (kick || netif_xmit_stopped(txq)) { > > > > + if (use_napi) > > > > + kick = __netdev_tx_sent_queue(txq, bytes, more); > > > > + else > > > > + kick = !more || netif_xmit_stopped(txq); > > > > + > > > > + if (kick) { > > > > if (virt...

...gt; >And transaction rate does increase if we coalesces more tx interurpts. > >> > >> > >>It's possible that we are deferring kicks too much due to BQL. > >> > >>As an experiment: do we get any of it back if we do > >>- if (kick || netif_xmit_stopped(txq)) > >>- virtqueue_kick(sq->vq); > >>+ virtqueue_kick(sq->vq); > >>? > > > > > >I will try, but during TCP_RR, at most 1 packets were pending, > >I suspect if BQL can help in this case. > > Looks like this h...

...gt; >And transaction rate does increase if we coalesces more tx interurpts. > >> > >> > >>It's possible that we are deferring kicks too much due to BQL. > >> > >>As an experiment: do we get any of it back if we do > >>- if (kick || netif_xmit_stopped(txq)) > >>- virtqueue_kick(sq->vq); > >>+ virtqueue_kick(sq->vq); > >>? > > > > > >I will try, but during TCP_RR, at most 1 packets were pending, > >I suspect if BQL can help in this case. > > Looks like this h...