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

Ferruh Yigit ferruh.yigit at intel.com
Wed Feb 8 19:02:51 CET 2017


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?

Thanks,
ferruh

> 
>> 1.8.3.1
> 



More information about the dev mailing list