[dpdk-dev] [PATCH v2] drivers/net/i40e/i40e_fdir.c: Improved i40e FDIR programming times

[Michael Lilja <ml@napatech.com>]

During my work (https://www.napatech.com/hw-acceleration-via-rte_flow/)
on a flowtable application example that use rte_flow I discovered
that the rte_flow programming times on a i40e was +11ms. The patch
below result in an average programming time of 22usec with a max of
60usec instead of +11ms.

Could the following patch be useful? There might be a good reason
for the original code, I'm unable to tell, so I will let it up
to the maintainer to decide.

Signed-off-by: Michael Lilja <ml@napatech.com>

---
v2:
* Code style fix
---
 drivers/net/i40e/i40e_fdir.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/net/i40e/i40e_fdir.c b/drivers/net/i40e/i40e_fdir.c
index 28cc554f5..2162443f5 100644
--- a/drivers/net/i40e/i40e_fdir.c
+++ b/drivers/net/i40e/i40e_fdir.c
@@ -1296,23 +1296,28 @@ i40e_fdir_filter_programming(struct i40e_pf *pf,
        rte_wmb();
        I40E_PCI_REG_WRITE(txq->qtx_tail, txq->tx_tail);

-       for (i = 0; i < I40E_FDIR_WAIT_COUNT; i++) {
-               rte_delay_us(I40E_FDIR_WAIT_INTERVAL_US);
+       for (i = 0; i < (I40E_FDIR_WAIT_COUNT * I40E_FDIR_WAIT_INTERVAL_US); i++) {
                if ((txdp->cmd_type_offset_bsz &
-                               rte_cpu_to_le_64(I40E_TXD_QW1_DTYPE_MASK)) ==
-                               rte_cpu_to_le_64(I40E_TX_DESC_DTYPE_DESC_DONE))
+                       rte_cpu_to_le_64(I40E_TXD_QW1_DTYPE_MASK)) ==
+                       rte_cpu_to_le_64(I40E_TX_DESC_DTYPE_DESC_DONE))
                        break;
+               rte_delay_us(1);
        }
-       if (i >= I40E_FDIR_WAIT_COUNT) {
+       if (i >= (I40E_FDIR_WAIT_COUNT * I40E_FDIR_WAIT_INTERVAL_US)) {
                PMD_DRV_LOG(ERR, "Failed to program FDIR filter:"
-                           " time out to get DD on tx queue.");
+                       " time out to get DD on tx queue.");
                return -ETIMEDOUT;
        }
        /* totally delay 10 ms to check programming status*/
-       rte_delay_us((I40E_FDIR_WAIT_COUNT - i) * I40E_FDIR_WAIT_INTERVAL_US);
+       for (i = 0; i < (I40E_FDIR_WAIT_COUNT * I40E_FDIR_WAIT_INTERVAL_US); i++) {
+               if (i40e_check_fdir_programming_status(rxq) >= 0) {
+                       break;
+               }
+               rte_delay_us(1);
+       }
        if (i40e_check_fdir_programming_status(rxq) < 0) {
                PMD_DRV_LOG(ERR, "Failed to program FDIR filter:"
-                           " programming status reported.");
+                               " programming status reported.");
                return -ENOSYS;
        }

--
2.12.2

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