i40e: use WC store to update queue tail registers

Nicolau, Radu Mon, 20 Jul 2020 01:55:01 -0700


On 7/20/2020 7:46 AM, Ruifeng Wang wrote:

-----Original Message-----
From: Radu Nicolau <radu.nico...@intel.com>
Sent: Friday, July 17, 2020 6:50 PM
To: dev@dpdk.org
Cc: beilei.x...@intel.com; jia....@intel.com; bruce.richard...@intel.com;
konstantin.anan...@intel.com; jerinjac...@gmail.com;
david.march...@redhat.com; fiona.tr...@intel.com; wei.zh...@intel.com;
Ruifeng Wang <ruifeng.w...@arm.com>; Radu Nicolau
<radu.nico...@intel.com>
Subject: [PATCH v8 2/4] net/i40e: use WC store to update queue tail registers

Performance improvement: use a write combining store instead of a regular
mmio write to update queue tail registers.

Signed-off-by: Radu Nicolau <radu.nico...@intel.com>
Acked-by: Bruce Richardson <bruce.richard...@intel.com>
---
  drivers/net/i40e/base/i40e_osdep.h    | 5 +++++
  drivers/net/i40e/i40e_rxtx.c          | 8 ++++----
  drivers/net/i40e/i40e_rxtx_vec_avx2.c | 4 ++--
drivers/net/i40e/i40e_rxtx_vec_sse.c  | 4 ++--
  4 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/net/i40e/base/i40e_osdep.h
b/drivers/net/i40e/base/i40e_osdep.h
index 58be396..69ab717 100644
--- a/drivers/net/i40e/base/i40e_osdep.h
+++ b/drivers/net/i40e/base/i40e_osdep.h
@@ -138,6 +138,11 @@ static inline uint32_t i40e_read_addr(volatile void
*addr)
  #define I40E_PCI_REG_WRITE_RELAXED(reg, value)        \
        rte_write32_relaxed((rte_cpu_to_le_32(value)), reg)

+#define I40E_PCI_REG_WC_WRITE(queue, reg, value) \

'queue' is not necessary since it will not be used. It can be removed?

Yes, I will remove it - in the first version we had a flag in the queuestruct, and this macro was not properly updated.


Thanks.
/Ruifeng

+       rte_write32_wc((rte_cpu_to_le_32(value)), reg) #define
+I40E_PCI_REG_WC_WRITE_RELAXED(queue, reg, value) \
+       rte_write32_wc_relaxed((rte_cpu_to_le_32(value)), reg)
+
  #define I40E_WRITE_FLUSH(a) I40E_READ_REG(a, I40E_GLGEN_STAT)
#define I40EVF_WRITE_FLUSH(a) I40E_READ_REG(a, I40E_VFGEN_RSTAT)

diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c index
840b6f3..64e43ac 100644
--- a/drivers/net/i40e/i40e_rxtx.c
+++ b/drivers/net/i40e/i40e_rxtx.c
@@ -760,7 +760,7 @@ i40e_recv_pkts(void *rx_queue, struct rte_mbuf
**rx_pkts, uint16_t nb_pkts)
        if (nb_hold > rxq->rx_free_thresh) {
                rx_id = (uint16_t) ((rx_id == 0) ?
                        (rxq->nb_rx_desc - 1) : (rx_id - 1));
-               I40E_PCI_REG_WRITE(rxq->qrx_tail, rx_id);
+               I40E_PCI_REG_WC_WRITE(rxq, rxq->qrx_tail, rx_id);
                nb_hold = 0;
        }
        rxq->nb_rx_hold = nb_hold;
@@ -938,7 +938,7 @@ i40e_recv_scattered_pkts(void *rx_queue,
        if (nb_hold > rxq->rx_free_thresh) {
                rx_id = (uint16_t)(rx_id == 0 ?
                        (rxq->nb_rx_desc - 1) : (rx_id - 1));
-               I40E_PCI_REG_WRITE(rxq->qrx_tail, rx_id);
+               I40E_PCI_REG_WC_WRITE(rxq, rxq->qrx_tail, rx_id);
                nb_hold = 0;
        }
        rxq->nb_rx_hold = nb_hold;
@@ -1249,7 +1249,7 @@ i40e_xmit_pkts(void *tx_queue, struct rte_mbuf
**tx_pkts, uint16_t nb_pkts)
                   (unsigned) tx_id, (unsigned) nb_tx);

        rte_cio_wmb();
-       I40E_PCI_REG_WRITE_RELAXED(txq->qtx_tail, tx_id);
+       I40E_PCI_REG_WC_WRITE_RELAXED(txq, txq->qtx_tail, tx_id);
        txq->tx_tail = tx_id;

        return nb_tx;
@@ -1400,7 +1400,7 @@ tx_xmit_pkts(struct i40e_tx_queue *txq,
                txq->tx_tail = 0;

        /* Update the tx tail register */
-       I40E_PCI_REG_WRITE(txq->qtx_tail, txq->tx_tail);
+       I40E_PCI_REG_WC_WRITE(txq, txq->qtx_tail, txq->tx_tail);

        return nb_pkts;
  }
diff --git a/drivers/net/i40e/i40e_rxtx_vec_avx2.c
b/drivers/net/i40e/i40e_rxtx_vec_avx2.c
index 3bcef13..294c1c4 100644
--- a/drivers/net/i40e/i40e_rxtx_vec_avx2.c
+++ b/drivers/net/i40e/i40e_rxtx_vec_avx2.c
@@ -134,7 +134,7 @@ i40e_rxq_rearm(struct i40e_rx_queue *rxq)
                             (rxq->nb_rx_desc - 1) : (rxq->rxrearm_start - 1));

        /* Update the tail pointer on the NIC */
-       I40E_PCI_REG_WRITE(rxq->qrx_tail, rx_id);
+       I40E_PCI_REG_WC_WRITE(rxq, rxq->qrx_tail, rx_id);
  }

  #ifndef RTE_LIBRTE_I40E_16BYTE_RX_DESC
@@ -921,7 +921,7 @@ i40e_xmit_fixed_burst_vec_avx2(void *tx_queue,
struct rte_mbuf **tx_pkts,

        txq->tx_tail = tx_id;

-       I40E_PCI_REG_WRITE(txq->qtx_tail, txq->tx_tail);
+       I40E_PCI_REG_WC_WRITE(txq, txq->qtx_tail, txq->tx_tail);

        return nb_pkts;
  }
diff --git a/drivers/net/i40e/i40e_rxtx_vec_sse.c
b/drivers/net/i40e/i40e_rxtx_vec_sse.c
index 6985183..a4635e0 100644
--- a/drivers/net/i40e/i40e_rxtx_vec_sse.c
+++ b/drivers/net/i40e/i40e_rxtx_vec_sse.c
@@ -86,7 +86,7 @@ i40e_rxq_rearm(struct i40e_rx_queue *rxq)
                             (rxq->nb_rx_desc - 1) : (rxq->rxrearm_start - 1));

        /* Update the tail pointer on the NIC */
-       I40E_PCI_REG_WRITE(rxq->qrx_tail, rx_id);
+       I40E_PCI_REG_WC_WRITE(rxq, rxq->qrx_tail, rx_id);
  }

  #ifndef RTE_LIBRTE_I40E_16BYTE_RX_DESC
@@ -733,7 +733,7 @@ i40e_xmit_fixed_burst_vec(void *tx_queue, struct
rte_mbuf **tx_pkts,

        txq->tx_tail = tx_id;

-       I40E_PCI_REG_WRITE(txq->qtx_tail, txq->tx_tail);
+       I40E_PCI_REG_WC_WRITE(txq, txq->qtx_tail, txq->tx_tail);

        return nb_pkts;
  }
--
2.7.4

Re: [dpdk-dev] [PATCH v8 2/4] net/i40e: use WC store to update queue tail registers

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