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?
> +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?
> + 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 ?
> +
> + /* 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?
> + 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;
> +}
