Ping.
Best regards, Ilya Maximets.
On 19.10.2016 17:07, Ilya Maximets wrote:
> The only reason why bulk alloc disabled for the rings with
> more than (I40E_MAX_RING_DESC - RTE_PMD_I40E_RX_MAX_BURST)
> descriptors is the possible out-of-bound access to the dma
> memory. But it's the artificial limit and can be easily
> avoided by allocating of RTE_PMD_I40E_RX_MAX_BURST more
> descriptors in memory. This will not interfere the HW and,
> as soon as all rings' memory zeroized, Rx functions will
> work correctly.
>
> This change allows to use vectorized Rx functions with
> 4096 descriptors in Rx ring which is important to achieve
> zero packet drop rate in high-load installations.
>
> Signed-off-by: Ilya Maximets <i.maximets at samsung.com>
> ---
> drivers/net/i40e/i40e_rxtx.c | 24 +++++++++++++-----------
> 1 file changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c
> index 7ae7d9f..1f76691 100644
> --- a/drivers/net/i40e/i40e_rxtx.c
> +++ b/drivers/net/i40e/i40e_rxtx.c
> @@ -409,15 +409,6 @@ check_rx_burst_bulk_alloc_preconditions(__rte_unused
> struct i40e_rx_queue *rxq)
> "rxq->rx_free_thresh=%d",
> rxq->nb_rx_desc, rxq->rx_free_thresh);
> ret = -EINVAL;
> - } else if (!(rxq->nb_rx_desc < (I40E_MAX_RING_DESC -
> - RTE_PMD_I40E_RX_MAX_BURST))) {
> - PMD_INIT_LOG(DEBUG, "Rx Burst Bulk Alloc Preconditions: "
> - "rxq->nb_rx_desc=%d, "
> - "I40E_MAX_RING_DESC=%d, "
> - "RTE_PMD_I40E_RX_MAX_BURST=%d",
> - rxq->nb_rx_desc, I40E_MAX_RING_DESC,
> - RTE_PMD_I40E_RX_MAX_BURST);
> - ret = -EINVAL;
> }
> #else
> ret = -EINVAL;
> @@ -1698,8 +1689,19 @@ i40e_dev_rx_queue_setup(struct rte_eth_dev *dev,
> rxq->rx_deferred_start = rx_conf->rx_deferred_start;
>
> /* Allocate the maximun number of RX ring hardware descriptor. */
> - ring_size = sizeof(union i40e_rx_desc) * I40E_MAX_RING_DESC;
> - ring_size = RTE_ALIGN(ring_size, I40E_DMA_MEM_ALIGN);
> + len = I40E_MAX_RING_DESC;
> +
> +#ifdef RTE_LIBRTE_I40E_RX_ALLOW_BULK_ALLOC
> + /**
> + * Allocating a little more memory because vectorized/bulk_alloc Rx
> + * functions doesn't check boundaries each time.
> + */
> + len += RTE_PMD_I40E_RX_MAX_BURST;
> +#endif
> +
> + ring_size = RTE_ALIGN(len * sizeof(union i40e_rx_desc),
> + I40E_DMA_MEM_ALIGN);
> +
> rz = rte_eth_dma_zone_reserve(dev, "rx_ring", queue_idx,
> ring_size, I40E_RING_BASE_ALIGN, socket_id);
> if (!rz) {
>
