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[dpdk-dev,v3,1/2] net/ixgbe: calculate the correct number of received packets in bulk alloc function

Message ID 1486226225-29997-1-git-send-email-jianbo.liu@linaro.org (mailing list archive)
State Superseded, archived
Delegated to: Ferruh Yigit
Headers

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel compilation success Compilation OK

Commit Message

Jianbo Liu Feb. 4, 2017, 4:37 p.m. UTC 
  To get better performance, Rx bulk alloc recv function will scan 8 descs
in one time, but the statuses are not consistent on ARM platform because
the memory allocated for Rx descriptors is cacheable hugepages.
This patch is to calculate the number of received packets by scan DD bit
sequentially, and stops when meeting the first packet with DD bit unset.

Signed-off-by: Jianbo Liu <jianbo.liu@linaro.org>
---
 drivers/net/ixgbe/ixgbe_rxtx.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

Comments

Jianbo Liu Feb. 4, 2017, 4:39 p.m. UTC | #1 
On 5 February 2017 at 00:37, Jianbo Liu <jianbo.liu@linaro.org> wrote:
> To get better performance, Rx bulk alloc recv function will scan 8 descs
> in one time, but the statuses are not consistent on ARM platform because
> the memory allocated for Rx descriptors is cacheable hugepages.
> This patch is to calculate the number of received packets by scan DD bit
> sequentially, and stops when meeting the first packet with DD bit unset.
>
> Signed-off-by: Jianbo Liu <jianbo.liu@linaro.org>
> ---
>  drivers/net/ixgbe/ixgbe_rxtx.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
> index 36f1c02..613890e 100644
> --- a/drivers/net/ixgbe/ixgbe_rxtx.c
> +++ b/drivers/net/ixgbe/ixgbe_rxtx.c

There is no change for this patch from v2 to v3.
But the other in this patchset, reading desc statuses is changed to be
in order, not backward.
diff mbox

Patch

diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
index 36f1c02..613890e 100644
--- a/drivers/net/ixgbe/ixgbe_rxtx.c
+++ b/drivers/net/ixgbe/ixgbe_rxtx.c
@@ -1460,17 +1460,19 @@  static inline int __attribute__((always_inline))
 	for (i = 0; i < RTE_PMD_IXGBE_RX_MAX_BURST;
 	     i += LOOK_AHEAD, rxdp += LOOK_AHEAD, rxep += LOOK_AHEAD) {
 		/* Read desc statuses backwards to avoid race condition */
-		for (j = LOOK_AHEAD-1; j >= 0; --j)
+		for (j = 0; j < LOOK_AHEAD; j++)
 			s[j] = rte_le_to_cpu_32(rxdp[j].wb.upper.status_error);
 
-		for (j = LOOK_AHEAD - 1; j >= 0; --j)
-			pkt_info[j] = rte_le_to_cpu_32(rxdp[j].wb.lower.
-						       lo_dword.data);
+		rte_smp_rmb();
 
 		/* Compute how many status bits were set */
-		nb_dd = 0;
-		for (j = 0; j < LOOK_AHEAD; ++j)
-			nb_dd += s[j] & IXGBE_RXDADV_STAT_DD;
+		for (nb_dd = 0; nb_dd < LOOK_AHEAD &&
+				(s[nb_dd] & IXGBE_RXDADV_STAT_DD); nb_dd++)
+			;
+
+		for (j = 0; j < nb_dd; j++)
+			pkt_info[j] = rte_le_to_cpu_32(rxdp[j].wb.lower.
+						       lo_dword.data);
 
 		nb_rx += nb_dd;