[dpdk-dev] [PATCH v2 1/2] net/ixgbe: calculate the correct number of received packets in bulk alloc function

[Ananyev, Konstantin]

Hi Ferruh,

> 
> On 2/4/2017 1:26 PM, Ananyev, Konstantin 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 at 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
> >> @@ -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;
> >>
> >> --
> >
> > Acked-by: Konstantin Ananyev <konstantin.ananyev at intel.com>
> 
> Hi Konstantin,
> 
> Is the ack valid for v3 and both patches?

No, I didn't look into the second one in details.
It is ARM specific, and I left it for people who are more familiar with ARM then me :)
Konstantin

> 
> Thanks,
> ferruh
> 
> >
> >> 1.8.3.1
> >