[dpdk-dev] [PATCH] i40e: enable i40e pmd on ARM platform

[Jianbo Liu]

On 3 August 2016 at 11:26, Yao, Lei A <lei.a.yao at intel.com> wrote:
> Hi, Jianbo
>
> I have tested you patch on my X86 platform,  the single core performance for Non-vector PMD will have about 1Mpps drop
> Non-vector PMD single core performance with patch               :  ~33.9 Mpps
> Non-vector PMD single core performance without patch        :  ~35.1 Mpps
> Is there any way to avoid such performance drop on X86? Thanks.
>

I think we can place a compiling condition before rte_rmb() to avoid
performance decrease on x86.
For example:  #if defined(RTE_ARCH_ARM) || defined(RTE_ARCH_ARM64)

Thanks!
Jianbo

> BRs
> Lei
>
> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Jianbo Liu
> Sent: Tuesday, August 2, 2016 2:58 PM
> To: dev at dpdk.org; Zhang, Helin <helin.zhang at intel.com>; Wu, Jingjing <jingjing.wu at intel.com>
> Cc: Jianbo Liu <jianbo.liu at linaro.org>
> Subject: [dpdk-dev] [PATCH] i40e: enable i40e pmd on ARM platform
>
> And add read memory barrier to avoid status inconsistency between two RX descriptors readings.
>
> Signed-off-by: Jianbo Liu <jianbo.liu at linaro.org>
> ---
>  config/defconfig_arm64-armv8a-linuxapp-gcc | 2 +-
>  doc/guides/nics/overview.rst               | 2 +-
>  drivers/net/i40e/i40e_rxtx.c               | 2 ++
>  3 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/config/defconfig_arm64-armv8a-linuxapp-gcc b/config/defconfig_arm64-armv8a-linuxapp-gcc
> index 1a17126..08f282b 100644
> --- a/config/defconfig_arm64-armv8a-linuxapp-gcc
> +++ b/config/defconfig_arm64-armv8a-linuxapp-gcc
> @@ -46,6 +46,6 @@ CONFIG_RTE_EAL_IGB_UIO=n
>
>  CONFIG_RTE_LIBRTE_IVSHMEM=n
>  CONFIG_RTE_LIBRTE_FM10K_PMD=n
> -CONFIG_RTE_LIBRTE_I40E_PMD=n
> +CONFIG_RTE_LIBRTE_I40E_INC_VECTOR=n
>
>  CONFIG_RTE_SCHED_VECTOR=n
> diff --git a/doc/guides/nics/overview.rst b/doc/guides/nics/overview.rst index 6abbae6..5175591 100644
> --- a/doc/guides/nics/overview.rst
> +++ b/doc/guides/nics/overview.rst
> @@ -138,7 +138,7 @@ Most of these differences are summarized below.
>     Linux VFIO                     Y Y   Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y                     Y   Y Y
>     Other kdrv                                                         Y Y               Y
>     ARMv7                                                                        Y             Y Y
> -   ARMv8                                              Y Y Y Y                   Y         Y   Y Y
> +   ARMv8                                  Y           Y Y Y Y                   Y         Y   Y Y
>     Power8                                                             Y Y       Y
>     TILE-Gx                                                                      Y
>     x86-32                         Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y       Y           Y Y Y
> diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c index 554d167..4004b8e 100644
> --- a/drivers/net/i40e/i40e_rxtx.c
> +++ b/drivers/net/i40e/i40e_rxtx.c
> @@ -994,6 +994,8 @@ i40e_rx_scan_hw_ring(struct i40e_rx_queue *rxq)
>                                         I40E_RXD_QW1_STATUS_SHIFT;
>                 }
>
> +               rte_rmb();
> +
>                 /* Compute how many status bits were set */
>                 for (j = 0, nb_dd = 0; j < I40E_LOOK_AHEAD; j++)
>                         nb_dd += s[j] & (1 << I40E_RX_DESC_STATUS_DD_SHIFT);
> --
> 2.4.11
>