[PATCH v3 1/2] net/ixgbe: calculate the correct number of received packets in bulk alloc function
From: Jianbo Liu <hidden>
Date: 2017-02-04 16:37:29
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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 <redacted> --- 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@@ -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;
--
1.8.3.1