liquidio: xmit_more support

Defer ringing the Tx doorbell if skb->xmit_more is set unless the Tx queue
is full or stopped.  To keep latency low, use a deferral limit of 8
packets.  We chose 8 because Octeon can fetch at most 8 packets in a single
PCI read, and our tests show that 8 results in low latency.

Signed-off-by: Intiyaz Basha <intiyaz.basha@cavium.com>
Signed-off-by: Satanand Burla <satananda.burla@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Intiyaz Basha 2017-10-26 16:18:20 -07:00 committed by David S. Miller
parent bc4747514a
commit c859e21a35
9 changed files with 55 additions and 19 deletions

View File

@ -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)

View File

@ -2594,7 +2594,8 @@ 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;
@ -2629,7 +2630,7 @@ 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);
@ -2663,7 +2664,7 @@ 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;
@ -2868,17 +2869,19 @@ 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);
@ -2897,6 +2900,9 @@ lio_xmit_failed:
if (dptr)
dma_unmap_single(&oct->pci_dev->dev, dptr,
ndata.datasize, DMA_TO_DEVICE);
octeon_ring_doorbell_locked(oct, iq_no);
tx_buffer_free(skb);
return NETDEV_TX_OK;
}

View File

@ -1690,7 +1690,8 @@ 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;
@ -1720,7 +1721,7 @@ 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);
@ -1752,6 +1753,7 @@ 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;
@ -1940,10 +1942,12 @@ 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;
@ -1952,7 +1956,7 @@ 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);
@ -1972,6 +1976,9 @@ lio_xmit_failed:
if (dptr)
dma_unmap_single(&oct->pci_dev->dev, dptr,
ndata.datasize, DMA_TO_DEVICE);
octeon_ring_doorbell_locked(oct, iq_no);
tx_buffer_free(skb);
return NETDEV_TX_OK;
}

View File

@ -37,6 +37,8 @@
#define MAX_OCTEON_LINKS MAX_OCTEON_NICIF
#define MAX_OCTEON_MULTICAST_ADDR 32
#define MAX_OCTEON_FILL_COUNT 8
/* CN6xxx IQ configuration macros */
#define CN6XXX_MAX_INPUT_QUEUES 32
#define CN6XXX_MAX_IQ_DESCRIPTORS 2048

View File

@ -343,6 +343,9 @@ int octeon_delete_instr_queue(struct octeon_device *octeon_dev, u32 iq_no);
int lio_wait_for_instr_fetch(struct octeon_device *oct);
void
octeon_ring_doorbell_locked(struct octeon_device *oct, u32 iq_no);
int
octeon_register_reqtype_free_fn(struct octeon_device *oct, int reqtype,
void (*fn)(void *));

View File

@ -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);

View File

@ -82,9 +82,10 @@ octeon_alloc_soft_command_resp(struct octeon_device *oct,
}
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,

View File

@ -279,7 +279,8 @@ octeon_alloc_soft_command_resp(struct octeon_device *oct,
* 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

View File

@ -278,6 +278,18 @@ ring_doorbell(struct octeon_device *oct, struct octeon_instr_queue *iq)
}
}
void
octeon_ring_doorbell_locked(struct octeon_device *oct, u32 iq_no)
{
struct octeon_instr_queue *iq;
iq = oct->instr_queue[iq_no];
spin_lock(&iq->post_lock);
if (iq->fill_cnt)
ring_doorbell(oct, iq);
spin_unlock(&iq->post_lock);
}
static inline void __copy_cmd_into_iq(struct octeon_instr_queue *iq,
u8 *cmd)
{
@ -543,6 +555,7 @@ octeon_send_command(struct octeon_device *oct, u32 iq_no,
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 +567,13 @@ octeon_send_command(struct octeon_device *oct, u32 iq_no,
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 (iq->fill_cnt >= MAX_OCTEON_FILL_COUNT || force_db ||
xmit_stopped || st.status == IQ_SEND_STOP)
ring_doorbell(oct, iq);
} else {
INCR_INSTRQUEUE_PKT_COUNT(oct, iq_no, instr_dropped, 1);