diff mbox series

[net-next] liquidio: xmit_more support

Message ID 20171018173602.GA14082@felix-thinkpad.cavium.com
State Changes Requested, archived
Delegated to: David Miller
Headers show
Series [net-next] liquidio: xmit_more support | expand

Commit Message

Manlunas, Felix Oct. 18, 2017, 5:36 p.m. UTC 
From: Intiyaz Basha <intiyaz.basha@cavium.com>

Do not write the Tx doorbell if skb->xmit_more is set unless the Tx
queue is full or stopped.

Signed-off-by: Intiyaz Basha <intiyaz.basha@cavium.com>
Signed-off-by: Derek Chickles <derek.chickles@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
---
 drivers/net/ethernet/cavium/liquidio/lio_core.c        |  6 ++++--
 drivers/net/ethernet/cavium/liquidio/lio_main.c        | 15 +++++++++------
 drivers/net/ethernet/cavium/liquidio/lio_vf_main.c     | 14 +++++++++-----
 drivers/net/ethernet/cavium/liquidio/octeon_main.h     |  2 +-
 drivers/net/ethernet/cavium/liquidio/octeon_nic.c      |  5 +++--
 drivers/net/ethernet/cavium/liquidio/octeon_nic.h      |  3 ++-
 drivers/net/ethernet/cavium/liquidio/request_manager.c |  5 +++--
 7 files changed, 31 insertions(+), 19 deletions(-)

Comments

David Miller Oct. 20, 2017, 12:18 p.m. UTC | #1 
From: Felix Manlunas <felix.manlunas@cavium.com>
Date: Wed, 18 Oct 2017 10:36:02 -0700

> From: Intiyaz Basha <intiyaz.basha@cavium.com>
> 
> Do not write the Tx doorbell if skb->xmit_more is set unless the Tx
> queue is full or stopped.
> 
> Signed-off-by: Intiyaz Basha <intiyaz.basha@cavium.com>
> Signed-off-by: Derek Chickles <derek.chickles@cavium.com>
> Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>

You're going to need some kind of added heuristic for this.

If the TX queue is idle, and then you get a full TX queue's
worth of xmit_more frames, you do not want to defer the doorbell
until the entire queue has been filled.

But that is what you are doing.

You have to experment with different deferral limit values to
see where latency starts to be negatively impacted.
diff mbox series

Patch

diff --git a/drivers/net/ethernet/cavium/liquidio/lio_core.c b/drivers/net/ethernet/cavium/liquidio/lio_core.c
index 23f6b60..b891d85 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_core.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_core.c
@@ -91,7 +91,7 @@  void octeon_update_tx_completion_counters(void *buf, int reqtype,
 	*bytes_compl += skb->len;
 }
 
-void octeon_report_sent_bytes_to_bql(void *buf, int reqtype)
+int octeon_report_sent_bytes_to_bql(void *buf, int reqtype)
 {
 	struct octnet_buf_free_info *finfo;
 	struct sk_buff *skb;
@@ -112,11 +112,13 @@  void octeon_report_sent_bytes_to_bql(void *buf, int reqtype)
 		break;
 
 	default:
-		return;
+		return 0;
 	}
 
 	txq = netdev_get_tx_queue(skb->dev, skb_get_queue_mapping(skb));
 	netdev_tx_sent_queue(txq, skb->len);
+
+	return netif_xmit_stopped(txq);
 }
 
 void liquidio_link_ctrl_cmd_completion(void *nctrl_ptr)
diff --git a/drivers/net/ethernet/cavium/liquidio/lio_main.c b/drivers/net/ethernet/cavium/liquidio/lio_main.c
index 963803b..f9a0e14 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_main.c
@@ -2479,7 +2479,8 @@  static void handle_timestamp(struct octeon_device *oct,
  */
 static inline int send_nic_timestamp_pkt(struct octeon_device *oct,
 					 struct octnic_data_pkt *ndata,
-					 struct octnet_buf_free_info *finfo)
+					 struct octnet_buf_free_info *finfo,
+					 int xmit_more)
 {
 	int retval;
 	struct octeon_soft_command *sc;
@@ -2514,7 +2515,7 @@  static inline int send_nic_timestamp_pkt(struct octeon_device *oct,
 		len = (u32)((struct octeon_instr_ih2 *)
 			    (&sc->cmd.cmd2.ih2))->dlengsz;
 
-	ring_doorbell = 1;
+	ring_doorbell = !xmit_more;
 
 	retval = octeon_send_command(oct, sc->iq_no, ring_doorbell, &sc->cmd,
 				     sc, len, ndata->reqtype);
@@ -2548,7 +2549,7 @@  static int liquidio_xmit(struct sk_buff *skb, struct net_device *netdev)
 	union tx_info *tx_info;
 	int status = 0;
 	int q_idx = 0, iq_no = 0;
-	int j;
+	int j, xmit_more = 0;
 	u64 dptr = 0;
 	u32 tag = 0;
 
@@ -2753,17 +2754,19 @@  static int liquidio_xmit(struct sk_buff *skb, struct net_device *netdev)
 		irh->vlan = skb_vlan_tag_get(skb) & 0xfff;
 	}
 
+	xmit_more = skb->xmit_more;
+
 	if (unlikely(cmdsetup.s.timestamp))
-		status = send_nic_timestamp_pkt(oct, &ndata, finfo);
+		status = send_nic_timestamp_pkt(oct, &ndata, finfo, xmit_more);
 	else
-		status = octnet_send_nic_data_pkt(oct, &ndata);
+		status = octnet_send_nic_data_pkt(oct, &ndata, xmit_more);
 	if (status == IQ_SEND_FAILED)
 		goto lio_xmit_failed;
 
 	netif_info(lio, tx_queued, lio->netdev, "Transmit queued successfully\n");
 
 	if (status == IQ_SEND_STOP)
-		stop_q(lio->netdev, q_idx);
+		stop_q(netdev, q_idx);
 
 	netif_trans_update(netdev);
 
diff --git a/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c b/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
index 2e993ce..a6a5dff 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
@@ -1691,7 +1691,8 @@  static void handle_timestamp(struct octeon_device *oct, u32 status, void *buf)
  */
 static int send_nic_timestamp_pkt(struct octeon_device *oct,
 				  struct octnic_data_pkt *ndata,
-				  struct octnet_buf_free_info *finfo)
+				  struct octnet_buf_free_info *finfo,
+				  int xmit_more)
 {
 	struct octeon_soft_command *sc;
 	int ring_doorbell;
@@ -1721,7 +1722,7 @@  static int send_nic_timestamp_pkt(struct octeon_device *oct,
 
 	len = (u32)((struct octeon_instr_ih3 *)(&sc->cmd.cmd3.ih3))->dlengsz;
 
-	ring_doorbell = 1;
+	ring_doorbell = !xmit_more;
 
 	retval = octeon_send_command(oct, sc->iq_no, ring_doorbell, &sc->cmd,
 				     sc, len, ndata->reqtype);
@@ -1753,6 +1754,7 @@  static int liquidio_xmit(struct sk_buff *skb, struct net_device *netdev)
 	struct octeon_device *oct;
 	int q_idx = 0, iq_no = 0;
 	union tx_info *tx_info;
+	int xmit_more = 0;
 	struct lio *lio;
 	int status = 0;
 	u64 dptr = 0;
@@ -1941,10 +1943,12 @@  static int liquidio_xmit(struct sk_buff *skb, struct net_device *netdev)
 		irh->vlan = skb_vlan_tag_get(skb) & VLAN_VID_MASK;
 	}
 
+	xmit_more = skb->xmit_more;
+
 	if (unlikely(cmdsetup.s.timestamp))
-		status = send_nic_timestamp_pkt(oct, &ndata, finfo);
+		status = send_nic_timestamp_pkt(oct, &ndata, finfo, xmit_more);
 	else
-		status = octnet_send_nic_data_pkt(oct, &ndata);
+		status = octnet_send_nic_data_pkt(oct, &ndata, xmit_more);
 	if (status == IQ_SEND_FAILED)
 		goto lio_xmit_failed;
 
@@ -1953,7 +1957,7 @@  static int liquidio_xmit(struct sk_buff *skb, struct net_device *netdev)
 	if (status == IQ_SEND_STOP) {
 		dev_err(&oct->pci_dev->dev, "Rcvd IQ_SEND_STOP signal; stopping IQ-%d\n",
 			iq_no);
-		stop_q(lio->netdev, q_idx);
+		stop_q(netdev, q_idx);
 	}
 
 	netif_trans_update(netdev);
diff --git a/drivers/net/ethernet/cavium/liquidio/octeon_main.h b/drivers/net/ethernet/cavium/liquidio/octeon_main.h
index 32ef3a7..c846eec 100644
--- a/drivers/net/ethernet/cavium/liquidio/octeon_main.h
+++ b/drivers/net/ethernet/cavium/liquidio/octeon_main.h
@@ -63,7 +63,7 @@  struct octnet_buf_free_info {
 };
 
 /* BQL-related functions */
-void octeon_report_sent_bytes_to_bql(void *buf, int reqtype);
+int octeon_report_sent_bytes_to_bql(void *buf, int reqtype);
 void octeon_update_tx_completion_counters(void *buf, int reqtype,
 					  unsigned int *pkts_compl,
 					  unsigned int *bytes_compl);
diff --git a/drivers/net/ethernet/cavium/liquidio/octeon_nic.c b/drivers/net/ethernet/cavium/liquidio/octeon_nic.c
index b457cf2..150609b 100644
--- a/drivers/net/ethernet/cavium/liquidio/octeon_nic.c
+++ b/drivers/net/ethernet/cavium/liquidio/octeon_nic.c
@@ -82,9 +82,10 @@ 
 }
 
 int octnet_send_nic_data_pkt(struct octeon_device *oct,
-			     struct octnic_data_pkt *ndata)
+			     struct octnic_data_pkt *ndata,
+			     int xmit_more)
 {
-	int ring_doorbell = 1;
+	int ring_doorbell = !xmit_more;
 
 	return octeon_send_command(oct, ndata->q_no, ring_doorbell, &ndata->cmd,
 				   ndata->buf, ndata->datasize,
diff --git a/drivers/net/ethernet/cavium/liquidio/octeon_nic.h b/drivers/net/ethernet/cavium/liquidio/octeon_nic.h
index 6480ef8..de4130d 100644
--- a/drivers/net/ethernet/cavium/liquidio/octeon_nic.h
+++ b/drivers/net/ethernet/cavium/liquidio/octeon_nic.h
@@ -279,7 +279,8 @@  static inline int octnet_iq_is_full(struct octeon_device *oct, u32 q_no)
  * queue should be stopped, and IQ_SEND_OK if it sent okay.
  */
 int octnet_send_nic_data_pkt(struct octeon_device *oct,
-			     struct octnic_data_pkt *ndata);
+			     struct octnic_data_pkt *ndata,
+			     int xmit_more);
 
 /** Send a NIC control packet to the device
  * @param oct - octeon device pointer
diff --git a/drivers/net/ethernet/cavium/liquidio/request_manager.c b/drivers/net/ethernet/cavium/liquidio/request_manager.c
index 1e0fbce..0086cda 100644
--- a/drivers/net/ethernet/cavium/liquidio/request_manager.c
+++ b/drivers/net/ethernet/cavium/liquidio/request_manager.c
@@ -543,6 +543,7 @@  static void check_db_timeout(struct work_struct *work)
 		    u32 force_db, void *cmd, void *buf,
 		    u32 datasize, u32 reqtype)
 {
+	int xmit_stopped;
 	struct iq_post_status st;
 	struct octeon_instr_queue *iq = oct->instr_queue[iq_no];
 
@@ -554,12 +555,12 @@  static void check_db_timeout(struct work_struct *work)
 	st = __post_command2(iq, cmd);
 
 	if (st.status != IQ_SEND_FAILED) {
-		octeon_report_sent_bytes_to_bql(buf, reqtype);
+		xmit_stopped = octeon_report_sent_bytes_to_bql(buf, reqtype);
 		__add_to_request_list(iq, st.index, buf, reqtype);
 		INCR_INSTRQUEUE_PKT_COUNT(oct, iq_no, bytes_sent, datasize);
 		INCR_INSTRQUEUE_PKT_COUNT(oct, iq_no, instr_posted, 1);
 
-		if (force_db)
+		if (force_db || xmit_stopped || st.status == IQ_SEND_STOP)
 			ring_doorbell(oct, iq);
 	} else {
 		INCR_INSTRQUEUE_PKT_COUNT(oct, iq_no, instr_dropped, 1);