Hi Eric, > -----Original Message----- > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Eric Kinzie > Sent: Thursday, June 25, 2015 7:26 PM > To: dev at dpdk.org > Subject: [dpdk-dev] [PATCH 2/2] ixgbe: add memory barriers in vector rx/tx > > Add write memory barrier before writing tail pointer. > > Fixes c95584dc2b18 ("ixgbe: new vectorized functions for Rx/Tx") > > Signed-off-by: Eric Kinzie <ehkinzie at gmail.com> > --- > drivers/net/ixgbe/ixgbe_rxtx_vec.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/net/ixgbe/ixgbe_rxtx_vec.c > b/drivers/net/ixgbe/ixgbe_rxtx_vec.c > index abd10f6..b601de8 100644 > --- a/drivers/net/ixgbe/ixgbe_rxtx_vec.c > +++ b/drivers/net/ixgbe/ixgbe_rxtx_vec.c > @@ -123,6 +123,7 @@ ixgbe_rxq_rearm(struct ixgbe_rx_queue *rxq) > (rxq->nb_rx_desc - 1) : (rxq->rxrearm_start - 1)); > > /* Update the tail pointer on the NIC */ > + rte_wmb(); > IXGBE_PCI_REG_WRITE(rxq->rdt_reg_addr, rx_id); > } > > @@ -645,6 +646,8 @@ ixgbe_xmit_pkts_vec(void *tx_queue, struct rte_mbuf > **tx_pkts, > > txq->tx_tail = tx_id; > > + /* update tail pointer */ > + rte_wmb(); > IXGBE_PCI_REG_WRITE(txq->tdt_reg_addr, txq->tx_tail); > > return nb_pkts;
There were several discussions about that subject already: why fence is not necessary here for IA and why we don't want to put it here: That I suppose was the last one: http://dpdk.org/ml/archives/dev/2015-April/016463.html As I can see, Dong already submitted patches for that: http://dpdk.org/dev/patchwork/patch/5884/ Though I didn't look at it closely yet. Konstantin > -- > 1.7.10.4
