From 5f07b3c51abe330c3dd702622c419efffb5757f0 Mon Sep 17 00:00:00 2001 From: Sathya Perla Date: Mon, 5 Jan 2015 05:48:34 -0500 Subject: [PATCH] be2net: support TX batching using skb->xmit_more flag This patch uses skb->xmit_more flag to batch TX requests. TX is flushed either when xmit_more is false or there is no more space in the TXQ. Skyhawk-R and BEx chips require an even number of wrbs to be posted. So, when a batch of TX requests is accumulated, the last header wrb may need to be fixed with an extra dummy wrb. This patch refactors be_xmit() routine as a sequence of be_xmit_enqueue() and be_xmit_flush() calls. The Tx completion code is also updated to be able to unmap/free a batch of skbs rather than a single skb. Signed-off-by: Sathya Perla Signed-off-by: David S. Miller --- drivers/net/ethernet/emulex/benet/be.h | 4 +- drivers/net/ethernet/emulex/benet/be_ethtool.c | 2 - drivers/net/ethernet/emulex/benet/be_hw.h | 5 + drivers/net/ethernet/emulex/benet/be_main.c | 238 +++++++++++++------------ 4 files changed, 133 insertions(+), 116 deletions(-) diff --git a/drivers/net/ethernet/emulex/benet/be.h b/drivers/net/ethernet/emulex/benet/be.h index 712e7f8..9fa2569 100644 --- a/drivers/net/ethernet/emulex/benet/be.h +++ b/drivers/net/ethernet/emulex/benet/be.h @@ -243,7 +243,6 @@ struct be_tx_stats { u64 tx_bytes; u64 tx_pkts; u64 tx_reqs; - u64 tx_wrbs; u64 tx_compl; ulong tx_jiffies; u32 tx_stops; @@ -266,6 +265,9 @@ struct be_tx_obj { /* Remember the skbs that were transmitted */ struct sk_buff *sent_skb_list[TX_Q_LEN]; struct be_tx_stats stats; + u16 pend_wrb_cnt; /* Number of WRBs yet to be given to HW */ + u16 last_req_wrb_cnt; /* wrb cnt of the last req in the Q */ + u16 last_req_hdr; /* index of the last req's hdr-wrb */ } ____cacheline_aligned_in_smp; /* Struct to remember the pages posted for rx frags */ diff --git a/drivers/net/ethernet/emulex/benet/be_ethtool.c b/drivers/net/ethernet/emulex/benet/be_ethtool.c index 73a500c..32c53bc0 100644 --- a/drivers/net/ethernet/emulex/benet/be_ethtool.c +++ b/drivers/net/ethernet/emulex/benet/be_ethtool.c @@ -193,8 +193,6 @@ static const struct be_ethtool_stat et_tx_stats[] = { {DRVSTAT_TX_INFO(tx_pkts)}, /* Number of skbs queued for trasmission by the driver */ {DRVSTAT_TX_INFO(tx_reqs)}, - /* Number of TX work request blocks DMAed to HW */ - {DRVSTAT_TX_INFO(tx_wrbs)}, /* Number of times the TX queue was stopped due to lack * of spaces in the TXQ. */ diff --git a/drivers/net/ethernet/emulex/benet/be_hw.h b/drivers/net/ethernet/emulex/benet/be_hw.h index 295ee08..6d7b3a4 100644 --- a/drivers/net/ethernet/emulex/benet/be_hw.h +++ b/drivers/net/ethernet/emulex/benet/be_hw.h @@ -311,6 +311,11 @@ struct amap_eth_hdr_wrb { u8 vlan_tag[16]; } __packed; +#define TX_HDR_WRB_COMPL 1 /* word 2 */ +#define TX_HDR_WRB_EVT (1 << 1) /* word 2 */ +#define TX_HDR_WRB_NUM_SHIFT 13 /* word 2: bits 13:17 */ +#define TX_HDR_WRB_NUM_MASK 0x1F /* word 2: bits 13:17 */ + struct be_eth_hdr_wrb { u32 dw[4]; }; diff --git a/drivers/net/ethernet/emulex/benet/be_main.c b/drivers/net/ethernet/emulex/benet/be_main.c index 41a0a54..37a26b0 100644 --- a/drivers/net/ethernet/emulex/benet/be_main.c +++ b/drivers/net/ethernet/emulex/benet/be_main.c @@ -662,41 +662,22 @@ void be_link_status_update(struct be_adapter *adapter, u8 link_status) netif_carrier_off(netdev); } -static void be_tx_stats_update(struct be_tx_obj *txo, - u32 wrb_cnt, u32 copied, u32 gso_segs, - bool stopped) +static void be_tx_stats_update(struct be_tx_obj *txo, struct sk_buff *skb) { struct be_tx_stats *stats = tx_stats(txo); u64_stats_update_begin(&stats->sync); stats->tx_reqs++; - stats->tx_wrbs += wrb_cnt; - stats->tx_bytes += copied; - stats->tx_pkts += (gso_segs ? gso_segs : 1); - if (stopped) - stats->tx_stops++; + stats->tx_bytes += skb->len; + stats->tx_pkts += (skb_shinfo(skb)->gso_segs ? : 1); u64_stats_update_end(&stats->sync); } -/* Determine number of WRB entries needed to xmit data in an skb */ -static u32 wrb_cnt_for_skb(struct be_adapter *adapter, struct sk_buff *skb, - bool *dummy) +/* Returns number of WRBs needed for the skb */ +static u32 skb_wrb_cnt(struct sk_buff *skb) { - int cnt = (skb->len > skb->data_len); - - cnt += skb_shinfo(skb)->nr_frags; - - /* to account for hdr wrb */ - cnt++; - if (lancer_chip(adapter) || !(cnt & 1)) { - *dummy = false; - } else { - /* add a dummy to make it an even num */ - cnt++; - *dummy = true; - } - BUG_ON(cnt > BE_MAX_TX_FRAG_COUNT); - return cnt; + /* +1 for the header wrb */ + return 1 + (skb_headlen(skb) ? 1 : 0) + skb_shinfo(skb)->nr_frags; } static inline void wrb_fill(struct be_eth_wrb *wrb, u64 addr, int len) @@ -770,11 +751,14 @@ static void wrb_fill_hdr(struct be_adapter *adapter, struct be_eth_hdr_wrb *hdr, SET_TX_WRB_HDR_BITS(vlan_tag, hdr, vlan_tag); } - /* To skip HW VLAN tagging: evt = 1, compl = 0 */ - SET_TX_WRB_HDR_BITS(complete, hdr, !skip_hw_vlan); - SET_TX_WRB_HDR_BITS(event, hdr, 1); SET_TX_WRB_HDR_BITS(num_wrb, hdr, wrb_cnt); SET_TX_WRB_HDR_BITS(len, hdr, len); + + /* Hack to skip HW VLAN tagging needs evt = 1, compl = 0 + * When this hack is not needed, the evt bit is set while ringing DB + */ + if (skip_hw_vlan) + SET_TX_WRB_HDR_BITS(event, hdr, 1); } static void unmap_tx_frag(struct device *dev, struct be_eth_wrb *wrb, @@ -794,22 +778,24 @@ static void unmap_tx_frag(struct device *dev, struct be_eth_wrb *wrb, } } -static int make_tx_wrbs(struct be_adapter *adapter, struct be_queue_info *txq, - struct sk_buff *skb, u32 wrb_cnt, bool dummy_wrb, - bool skip_hw_vlan) +/* Returns the number of WRBs used up by the skb */ +static u32 be_xmit_enqueue(struct be_adapter *adapter, struct be_tx_obj *txo, + struct sk_buff *skb, bool skip_hw_vlan) { - dma_addr_t busaddr; - int i, copied = 0; + u32 i, copied = 0, wrb_cnt = skb_wrb_cnt(skb); struct device *dev = &adapter->pdev->dev; - struct sk_buff *first_skb = skb; - struct be_eth_wrb *wrb; + struct be_queue_info *txq = &txo->q; struct be_eth_hdr_wrb *hdr; bool map_single = false; - u16 map_head; + struct be_eth_wrb *wrb; + dma_addr_t busaddr; + u16 head = txq->head; hdr = queue_head_node(txq); + wrb_fill_hdr(adapter, hdr, skb, wrb_cnt, skb->len, skip_hw_vlan); + be_dws_cpu_to_le(hdr, sizeof(*hdr)); + queue_head_inc(txq); - map_head = txq->head; if (skb->len > skb->data_len) { int len = skb_headlen(skb); @@ -839,19 +825,23 @@ static int make_tx_wrbs(struct be_adapter *adapter, struct be_queue_info *txq, copied += skb_frag_size(frag); } - if (dummy_wrb) { - wrb = queue_head_node(txq); - wrb_fill(wrb, 0, 0); - be_dws_cpu_to_le(wrb, sizeof(*wrb)); - queue_head_inc(txq); - } + BUG_ON(txo->sent_skb_list[head]); + txo->sent_skb_list[head] = skb; + txo->last_req_hdr = head; + atomic_add(wrb_cnt, &txq->used); + txo->last_req_wrb_cnt = wrb_cnt; + txo->pend_wrb_cnt += wrb_cnt; - wrb_fill_hdr(adapter, hdr, first_skb, wrb_cnt, copied, skip_hw_vlan); - be_dws_cpu_to_le(hdr, sizeof(*hdr)); + be_tx_stats_update(txo, skb); + return wrb_cnt; - return copied; dma_err: - txq->head = map_head; + /* Bring the queue back to the state it was in before this + * routine was invoked. + */ + txq->head = head; + /* skip the first wrb (hdr); it's not mapped */ + queue_head_inc(txq); while (copied) { wrb = queue_head_node(txq); unmap_tx_frag(dev, wrb, map_single); @@ -860,6 +850,7 @@ dma_err: adapter->drv_stats.dma_map_errors++; queue_head_inc(txq); } + txq->head = head; return 0; } @@ -1030,52 +1021,64 @@ static struct sk_buff *be_xmit_workarounds(struct be_adapter *adapter, return skb; } +static void be_xmit_flush(struct be_adapter *adapter, struct be_tx_obj *txo) +{ + struct be_queue_info *txq = &txo->q; + struct be_eth_hdr_wrb *hdr = queue_index_node(txq, txo->last_req_hdr); + + /* Mark the last request eventable if it hasn't been marked already */ + if (!(hdr->dw[2] & cpu_to_le32(TX_HDR_WRB_EVT))) + hdr->dw[2] |= cpu_to_le32(TX_HDR_WRB_EVT | TX_HDR_WRB_COMPL); + + /* compose a dummy wrb if there are odd set of wrbs to notify */ + if (!lancer_chip(adapter) && (txo->pend_wrb_cnt & 1)) { + wrb_fill(queue_head_node(txq), 0, 0); + queue_head_inc(txq); + atomic_inc(&txq->used); + txo->pend_wrb_cnt++; + hdr->dw[2] &= ~cpu_to_le32(TX_HDR_WRB_NUM_MASK << + TX_HDR_WRB_NUM_SHIFT); + hdr->dw[2] |= cpu_to_le32((txo->last_req_wrb_cnt + 1) << + TX_HDR_WRB_NUM_SHIFT); + } + be_txq_notify(adapter, txo, txo->pend_wrb_cnt); + txo->pend_wrb_cnt = 0; +} + static netdev_tx_t be_xmit(struct sk_buff *skb, struct net_device *netdev) { + bool skip_hw_vlan = false, flush = !skb->xmit_more; struct be_adapter *adapter = netdev_priv(netdev); - struct be_tx_obj *txo = &adapter->tx_obj[skb_get_queue_mapping(skb)]; + u16 q_idx = skb_get_queue_mapping(skb); + struct be_tx_obj *txo = &adapter->tx_obj[q_idx]; struct be_queue_info *txq = &txo->q; - bool dummy_wrb, stopped = false; - u32 wrb_cnt = 0, copied = 0; - bool skip_hw_vlan = false; - u32 start = txq->head; + u16 wrb_cnt; skb = be_xmit_workarounds(adapter, skb, &skip_hw_vlan); - if (!skb) { - tx_stats(txo)->tx_drv_drops++; - return NETDEV_TX_OK; - } - - wrb_cnt = wrb_cnt_for_skb(adapter, skb, &dummy_wrb); + if (unlikely(!skb)) + goto drop; - copied = make_tx_wrbs(adapter, txq, skb, wrb_cnt, dummy_wrb, - skip_hw_vlan); - if (copied) { - int gso_segs = skb_shinfo(skb)->gso_segs; + wrb_cnt = be_xmit_enqueue(adapter, txo, skb, skip_hw_vlan); + if (unlikely(!wrb_cnt)) { + dev_kfree_skb_any(skb); + goto drop; + } - /* record the sent skb in the sent_skb table */ - BUG_ON(txo->sent_skb_list[start]); - txo->sent_skb_list[start] = skb; + if ((atomic_read(&txq->used) + BE_MAX_TX_FRAG_COUNT) >= txq->len) { + netif_stop_subqueue(netdev, q_idx); + tx_stats(txo)->tx_stops++; + } - /* Ensure txq has space for the next skb; Else stop the queue - * *BEFORE* ringing the tx doorbell, so that we serialze the - * tx compls of the current transmit which'll wake up the queue - */ - atomic_add(wrb_cnt, &txq->used); - if ((BE_MAX_TX_FRAG_COUNT + atomic_read(&txq->used)) >= - txq->len) { - netif_stop_subqueue(netdev, skb_get_queue_mapping(skb)); - stopped = true; - } + if (flush || __netif_subqueue_stopped(netdev, q_idx)) + be_xmit_flush(adapter, txo); - be_txq_notify(adapter, txo, wrb_cnt); + return NETDEV_TX_OK; +drop: + tx_stats(txo)->tx_drv_drops++; + /* Flush the already enqueued tx requests */ + if (flush && txo->pend_wrb_cnt) + be_xmit_flush(adapter, txo); - be_tx_stats_update(txo, wrb_cnt, copied, gso_segs, stopped); - } else { - txq->head = start; - tx_stats(txo)->tx_drv_drops++; - dev_kfree_skb_any(skb); - } return NETDEV_TX_OK; } @@ -1959,32 +1962,34 @@ static struct be_eth_tx_compl *be_tx_compl_get(struct be_queue_info *tx_cq) static u16 be_tx_compl_process(struct be_adapter *adapter, struct be_tx_obj *txo, u16 last_index) { + struct sk_buff **sent_skbs = txo->sent_skb_list; struct be_queue_info *txq = &txo->q; + u16 frag_index, num_wrbs = 0; + struct sk_buff *skb = NULL; + bool unmap_skb_hdr = false; struct be_eth_wrb *wrb; - struct sk_buff **sent_skbs = txo->sent_skb_list; - struct sk_buff *sent_skb; - u16 cur_index, num_wrbs = 1; /* account for hdr wrb */ - bool unmap_skb_hdr = true; - - sent_skb = sent_skbs[txq->tail]; - BUG_ON(!sent_skb); - sent_skbs[txq->tail] = NULL; - - /* skip header wrb */ - queue_tail_inc(txq); do { - cur_index = txq->tail; + if (sent_skbs[txq->tail]) { + /* Free skb from prev req */ + if (skb) + dev_consume_skb_any(skb); + skb = sent_skbs[txq->tail]; + sent_skbs[txq->tail] = NULL; + queue_tail_inc(txq); /* skip hdr wrb */ + num_wrbs++; + unmap_skb_hdr = true; + } wrb = queue_tail_node(txq); + frag_index = txq->tail; unmap_tx_frag(&adapter->pdev->dev, wrb, - (unmap_skb_hdr && skb_headlen(sent_skb))); + (unmap_skb_hdr && skb_headlen(skb))); unmap_skb_hdr = false; - - num_wrbs++; queue_tail_inc(txq); - } while (cur_index != last_index); + num_wrbs++; + } while (frag_index != last_index); + dev_consume_skb_any(skb); - dev_consume_skb_any(sent_skb); return num_wrbs; } @@ -2068,12 +2073,11 @@ static void be_rx_cq_clean(struct be_rx_obj *rxo) static void be_tx_compl_clean(struct be_adapter *adapter) { + u16 end_idx, notified_idx, cmpl = 0, timeo = 0, num_wrbs = 0; + struct device *dev = &adapter->pdev->dev; struct be_tx_obj *txo; struct be_queue_info *txq; struct be_eth_tx_compl *txcp; - u16 end_idx, cmpl = 0, timeo = 0, num_wrbs = 0; - struct sk_buff *sent_skb; - bool dummy_wrb; int i, pending_txqs; /* Stop polling for compls when HW has been silent for 10ms */ @@ -2095,7 +2099,7 @@ static void be_tx_compl_clean(struct be_adapter *adapter) atomic_sub(num_wrbs, &txq->used); timeo = 0; } - if (atomic_read(&txq->used) == 0) + if (atomic_read(&txq->used) == txo->pend_wrb_cnt) pending_txqs--; } @@ -2105,21 +2109,29 @@ static void be_tx_compl_clean(struct be_adapter *adapter) mdelay(1); } while (true); + /* Free enqueued TX that was never notified to HW */ for_all_tx_queues(adapter, txo, i) { txq = &txo->q; - if (atomic_read(&txq->used)) - dev_err(&adapter->pdev->dev, "%d pending tx-compls\n", - atomic_read(&txq->used)); - /* free posted tx for which compls will never arrive */ - while (atomic_read(&txq->used)) { - sent_skb = txo->sent_skb_list[txq->tail]; + if (atomic_read(&txq->used)) { + dev_info(dev, "txq%d: cleaning %d pending tx-wrbs\n", + i, atomic_read(&txq->used)); + notified_idx = txq->tail; end_idx = txq->tail; - num_wrbs = wrb_cnt_for_skb(adapter, sent_skb, - &dummy_wrb); - index_adv(&end_idx, num_wrbs - 1, txq->len); + index_adv(&end_idx, atomic_read(&txq->used) - 1, + txq->len); + /* Use the tx-compl process logic to handle requests + * that were not sent to the HW. + */ num_wrbs = be_tx_compl_process(adapter, txo, end_idx); atomic_sub(num_wrbs, &txq->used); + BUG_ON(atomic_read(&txq->used)); + txo->pend_wrb_cnt = 0; + /* Since hw was never notified of these requests, + * reset TXQ indices + */ + txq->head = notified_idx; + txq->tail = notified_idx; } } } -- 2.7.4