On 6/25/19 5:08 PM, Jakub Kicinski wrote:
On Thu, 20 Jun 2019 13:24:20 -0700, Shannon Nelson wrote:Add both the Tx and Rx queue setup and handling. The related stats display come later. Instead of using the generic napi routines used by the slow-path command, the Tx and Rx paths are simplified and inlined in one file in order to get better compiler optimizations.Signed-off-by: Shannon Nelson <snel...@pensando.io> diff --git a/drivers/net/ethernet/pensando/ionic/ionic_debugfs.c b/drivers/net/ethernet/pensando/ionic/ionic_debugfs.c index 5ebfaa320edf..6dfcada9e822 100644 --- a/drivers/net/ethernet/pensando/ionic/ionic_debugfs.c +++ b/drivers/net/ethernet/pensando/ionic/ionic_debugfs.c @@ -351,6 +351,54 @@ int ionic_debugfs_add_qcq(struct lif *lif, struct qcq *qcq) desc_blob); }+ if (qcq->flags & QCQ_F_TX_STATS) {+ stats_dentry = debugfs_create_dir("tx_stats", q_dentry); + if (IS_ERR_OR_NULL(stats_dentry)) + return PTR_ERR(stats_dentry); + + debugfs_create_u64("dma_map_err", 0400, stats_dentry, + &qcq->stats->tx.dma_map_err); + debugfs_create_u64("pkts", 0400, stats_dentry, + &qcq->stats->tx.pkts); + debugfs_create_u64("bytes", 0400, stats_dentry, + &qcq->stats->tx.bytes); + debugfs_create_u64("clean", 0400, stats_dentry, + &qcq->stats->tx.clean); + debugfs_create_u64("linearize", 0400, stats_dentry, + &qcq->stats->tx.linearize); + debugfs_create_u64("no_csum", 0400, stats_dentry, + &qcq->stats->tx.no_csum); + debugfs_create_u64("csum", 0400, stats_dentry, + &qcq->stats->tx.csum); + debugfs_create_u64("crc32_csum", 0400, stats_dentry, + &qcq->stats->tx.crc32_csum); + debugfs_create_u64("tso", 0400, stats_dentry, + &qcq->stats->tx.tso); + debugfs_create_u64("frags", 0400, stats_dentry, + &qcq->stats->tx.frags);I wonder why debugfs over ethtool -S?
I believe this was from early engineering, before ethtool -S had been filled out. I'll clean that up.
+static int ionic_tx(struct queue *q, struct sk_buff *skb) +{ + struct tx_stats *stats = q_to_tx_stats(q); + int err; + + if (skb->ip_summed == CHECKSUM_PARTIAL) + err = ionic_tx_calc_csum(q, skb); + else + err = ionic_tx_calc_no_csum(q, skb); + if (err) + return err; + + err = ionic_tx_skb_frags(q, skb); + if (err) + return err; + + skb_tx_timestamp(skb); + stats->pkts++; + stats->bytes += skb->len;nit: I think counting stats on completion may be a better idea, otherwise when you can a full ring on stop your HW counters are guaranteed to be different than SW counters. Am I wrong?
You are not wrong, that is how many drivers handle it. I like seeing how much the driver was given (ethtool -S) versus how much the HW actually pushed out (netstat -i or ip -s link show). These numbers shouldn't be very often be very different, but it is interesting when they are.
+ ionic_txq_post(q, !netdev_xmit_more(), ionic_tx_clean, skb); + + return 0; +} + +static int ionic_tx_descs_needed(struct queue *q, struct sk_buff *skb) +{ + struct tx_stats *stats = q_to_tx_stats(q); + int err; + + /* If TSO, need roundup(skb->len/mss) descs */ + if (skb_is_gso(skb)) + return (skb->len / skb_shinfo(skb)->gso_size) + 1;This doesn't look correct, are you sure you don't want skb_shinfo(skb)->gso_segs ?
That would probably work as well.
+ + /* If non-TSO, just need 1 desc and nr_frags sg elems */ + if (skb_shinfo(skb)->nr_frags <= IONIC_TX_MAX_SG_ELEMS) + return 1; + + /* Too many frags, so linearize */ + err = skb_linearize(skb); + if (err) + return err; + + stats->linearize++; + + /* Need 1 desc and zero sg elems */ + return 1; +} + +netdev_tx_t ionic_start_xmit(struct sk_buff *skb, struct net_device *netdev) +{ + u16 queue_index = skb_get_queue_mapping(skb); + struct lif *lif = netdev_priv(netdev); + struct queue *q; + int ndescs; + int err; + + if (unlikely(!test_bit(LIF_UP, lif->state))) { + dev_kfree_skb(skb); + return NETDEV_TX_OK; + }Surely you stop TX before taking the queues down?
Yes, in ionic_lif_stop()
+ if (likely(lif_to_txqcq(lif, queue_index))) + q = lif_to_txq(lif, queue_index); + else + q = lif_to_txq(lif, 0); + + ndescs = ionic_tx_descs_needed(q, skb); + if (ndescs < 0) + goto err_out_drop; + + if (!ionic_q_has_space(q, ndescs)) { + netif_stop_subqueue(netdev, queue_index); + q->stop++; + + /* Might race with ionic_tx_clean, check again */ + smp_rmb(); + if (ionic_q_has_space(q, ndescs)) { + netif_wake_subqueue(netdev, queue_index); + q->wake++; + } else { + return NETDEV_TX_BUSY; + } + } + + if (skb_is_gso(skb)) + err = ionic_tx_tso(q, skb); + else + err = ionic_tx(q, skb); + + if (err) + goto err_out_drop; + + return NETDEV_TX_OK; + +err_out_drop: + q->drop++; + dev_kfree_skb(skb); + return NETDEV_TX_OK; +}
