From: Ilya Maximets <i.maximets@samsung.com>
To: dev@dpdk.org, Helin Zhang <helin.zhang@intel.com>,
Konstantin Ananyev <konstantin.ananyev@intel.com>,
Jingjing Wu <jingjing.wu@intel.com>
Cc: Dyasly Sergey <s.dyasly@samsung.com>,
Heetae Ahn <heetae82.ahn@samsung.com>,
Bruce Richardson <bruce.richardson@intel.com>
Subject: Re: [dpdk-dev] [PATCH RFC 2/2] net/ixgbe: allow bulk alloc for the max size desc ring
Date: Tue, 29 Nov 2016 13:59:24 +0300 [thread overview]
Message-ID: <ec0e4526-394f-9bcc-e467-6675b0c28477@samsung.com> (raw)
In-Reply-To: <1476886037-4586-3-git-send-email-i.maximets@samsung.com>
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 (IXGBE_MAX_RING_DESC - RTE_PMD_IXGBE_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_IXGBE_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@samsung.com>
> ---
> drivers/net/ixgbe/ixgbe_rxtx.c | 17 +----------------
> drivers/net/ixgbe/ixgbe_rxtx.h | 2 +-
> 2 files changed, 2 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
> index 2ce8234..07c04c3 100644
> --- a/drivers/net/ixgbe/ixgbe_rxtx.c
> +++ b/drivers/net/ixgbe/ixgbe_rxtx.c
> @@ -2585,7 +2585,6 @@ check_rx_burst_bulk_alloc_preconditions(struct ixgbe_rx_queue *rxq)
> * rxq->rx_free_thresh >= RTE_PMD_IXGBE_RX_MAX_BURST
> * rxq->rx_free_thresh < rxq->nb_rx_desc
> * (rxq->nb_rx_desc % rxq->rx_free_thresh) == 0
> - * rxq->nb_rx_desc<(IXGBE_MAX_RING_DESC-RTE_PMD_IXGBE_RX_MAX_BURST)
> * Scattered packets are not supported. This should be checked
> * outside of this function.
> */
> @@ -2607,15 +2606,6 @@ check_rx_burst_bulk_alloc_preconditions(struct ixgbe_rx_queue *rxq)
> "rxq->rx_free_thresh=%d",
> rxq->nb_rx_desc, rxq->rx_free_thresh);
> ret = -EINVAL;
> - } else if (!(rxq->nb_rx_desc <
> - (IXGBE_MAX_RING_DESC - RTE_PMD_IXGBE_RX_MAX_BURST))) {
> - PMD_INIT_LOG(DEBUG, "Rx Burst Bulk Alloc Preconditions: "
> - "rxq->nb_rx_desc=%d, "
> - "IXGBE_MAX_RING_DESC=%d, "
> - "RTE_PMD_IXGBE_RX_MAX_BURST=%d",
> - rxq->nb_rx_desc, IXGBE_MAX_RING_DESC,
> - RTE_PMD_IXGBE_RX_MAX_BURST);
> - ret = -EINVAL;
> }
>
> return ret;
> @@ -2632,12 +2622,7 @@ ixgbe_reset_rx_queue(struct ixgbe_adapter *adapter, struct ixgbe_rx_queue *rxq)
> /*
> * By default, the Rx queue setup function allocates enough memory for
> * IXGBE_MAX_RING_DESC. The Rx Burst bulk allocation function requires
> - * extra memory at the end of the descriptor ring to be zero'd out. A
> - * pre-condition for using the Rx burst bulk alloc function is that the
> - * number of descriptors is less than or equal to
> - * (IXGBE_MAX_RING_DESC - RTE_PMD_IXGBE_RX_MAX_BURST). Check all the
> - * constraints here to see if we need to zero out memory after the end
> - * of the H/W descriptor ring.
> + * extra memory at the end of the descriptor ring to be zero'd out.
> */
> if (adapter->rx_bulk_alloc_allowed)
> /* zero out extra memory */
> diff --git a/drivers/net/ixgbe/ixgbe_rxtx.h b/drivers/net/ixgbe/ixgbe_rxtx.h
> index 2608b36..1abc6f2 100644
> --- a/drivers/net/ixgbe/ixgbe_rxtx.h
> +++ b/drivers/net/ixgbe/ixgbe_rxtx.h
> @@ -67,7 +67,7 @@
> #define RTE_IXGBE_MAX_RX_BURST RTE_IXGBE_RXQ_REARM_THRESH
> #endif
>
> -#define RX_RING_SZ ((IXGBE_MAX_RING_DESC + RTE_IXGBE_DESCS_PER_LOOP - 1) * \
> +#define RX_RING_SZ ((IXGBE_MAX_RING_DESC + RTE_PMD_IXGBE_RX_MAX_BURST) * \
> sizeof(union ixgbe_adv_rx_desc))
>
> #ifdef RTE_PMD_PACKET_PREFETCH
>
next prev parent reply other threads:[~2016-11-29 10:59 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20161019140725eucas1p1cb53318d974fb1152f1a7b571f328fd5@eucas1p1.samsung.com>
2016-10-19 14:07 ` [dpdk-dev] [PATCH RFC 0/2] Allow vectorized Rx with 4096 desc ring size on Intel NICs Ilya Maximets
[not found] ` <CGME20161019140730eucas1p2b1cf9daba45bdbf915bb69b24a0a850f@eucas1p2.samsung.com>
2016-10-19 14:07 ` [dpdk-dev] [PATCH RFC 1/2] net/i40e: allow bulk alloc for the max size desc ring Ilya Maximets
2016-11-29 10:59 ` Ilya Maximets
2016-11-29 12:50 ` Ananyev, Konstantin
2016-11-29 13:06 ` Ilya Maximets
[not found] ` <CGME20161019140735eucas1p267bb4aa03547e70e5f13d78e2ffedcc4@eucas1p2.samsung.com>
2016-10-19 14:07 ` [dpdk-dev] [PATCH RFC 2/2] net/ixgbe: " Ilya Maximets
2016-11-29 10:59 ` Ilya Maximets [this message]
2016-10-19 14:30 ` [dpdk-dev] [PATCH RFC 0/2] Allow vectorized Rx with 4096 desc ring size on Intel NICs Ferruh Yigit
2016-11-21 13:53 ` Ferruh Yigit
2016-12-21 12:33 ` Ilya Maximets
2016-12-27 5:03 ` Ilya Maximets
2017-01-02 15:40 ` Thomas Monjalon
2017-01-03 17:24 ` Ferruh Yigit
2017-01-06 2:29 ` Wu, Jingjing
2017-01-06 13:56 ` Ferruh Yigit
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