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From: Jerin Jacob <jerinjacobk@gmail.com>
To: Gavin Hu <gavin.hu@arm.com>
Cc: dpdk-dev <dev@dpdk.org>, nd <nd@arm.com>,
	David Marchand <david.marchand@redhat.com>,
	 Thomas Monjalon <thomas@monjalon.net>,
	Jerin Jacob <jerinj@marvell.com>,
	 "Ye, Xiaolong" <xiaolong.ye@intel.com>,
	Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>,
	 "Ruifeng Wang (Arm Technology China)" <ruifeng.wang@arm.com>,
	Phil Yang <phil.yang@arm.com>,  Joyce Kong <joyce.kong@arm.com>,
	Steve Capper <steve.capper@arm.com>,
	dpdk stable <stable@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v1 1/3] net/i40e: relax barrier in the Tx fastpath of vPMD
Date: Fri, 6 Mar 2020 14:41:18 +0530
Message-ID: <CALBAE1PSkp3o3VvrrX_f_q8YRg_Q2T-4SkMCCgxMEbbjrB9vnw@mail.gmail.com> (raw)
In-Reply-To: <20200306050427.66114-2-gavin.hu@arm.com>

On Fri, Mar 6, 2020 at 10:35 AM Gavin Hu <gavin.hu@arm.com> wrote:
>
> To keep ordering of mixed accesses, rte_cio is sufficient.
> The rte_io barrier inside the I40E_PCI_REG_WRITE is overkill.[1]
>
> This patch fixes by replacing with just sufficient barriers in the
> normal PMD and vPMD.
>
> It showed 7% performance uplift on ThunderX2 and 4% on Arm N1SDP.
> The test case is the RFC2544 zero-loss test running testpmd.
>
> [1] http://inbox.dpdk.org/dev/CALBAE1M-ezVWCjqCZDBw+MMDEC4O9
> qf0Kpn89EMdGDajepKoZQ@mail.gmail.com
>
> Fixes: 4861cde46116 ("i40e: new poll mode driver")
> Cc: stable@dpdk.org
>
> Signed-off-by: Gavin Hu <gavin.hu@arm.com>

Acked-by: Jerin Jacob <jerinj@marvell.com>



> ---
>  drivers/net/i40e/i40e_rxtx_vec_neon.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/i40e/i40e_rxtx_vec_neon.c b/drivers/net/i40e/i40e_rxtx_vec_neon.c
> index deb185fe2..4376d8911 100644
> --- a/drivers/net/i40e/i40e_rxtx_vec_neon.c
> +++ b/drivers/net/i40e/i40e_rxtx_vec_neon.c
> @@ -72,8 +72,9 @@ i40e_rxq_rearm(struct i40e_rx_queue *rxq)
>         rx_id = (uint16_t)((rxq->rxrearm_start == 0) ?
>                              (rxq->nb_rx_desc - 1) : (rxq->rxrearm_start - 1));
>
> +       rte_cio_wmb();
>         /* Update the tail pointer on the NIC */
> -       I40E_PCI_REG_WRITE(rxq->qrx_tail, rx_id);
> +       I40E_PCI_REG_WRITE_RELAXED(rxq->qrx_tail, rx_id);
>  }
>
>  static inline void
> @@ -564,7 +565,8 @@ i40e_xmit_fixed_burst_vec(void *tx_queue, struct rte_mbuf **tx_pkts,
>
>         txq->tx_tail = tx_id;
>
> -       I40E_PCI_REG_WRITE(txq->qtx_tail, txq->tx_tail);
> +       rte_cio_wmb();
> +       I40E_PCI_REG_WRITE_RELAXED(txq->qtx_tail, tx_id);
>
>         return nb_pkts;
>  }
> --
> 2.17.1
>

  reply	other threads:[~2020-03-06  9:11 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-06  5:04 [dpdk-dev] [PATCH v1 0/3] i40e vPMD optimization on aarch64 Gavin Hu
2020-03-06  5:04 ` [dpdk-dev] [PATCH v1 1/3] net/i40e: relax barrier in the Tx fastpath of vPMD Gavin Hu
2020-03-06  9:11   ` Jerin Jacob [this message]
2020-03-06  5:04 ` [dpdk-dev] [PATCH v1 2/3] net/i40e: restrict pointer aliasing for neon vec Gavin Hu
2020-03-06  5:04 ` [dpdk-dev] [PATCH v1 3/3] net/i40e: auto-vectorization to speed up Tx free Gavin Hu
2020-03-06  7:44   ` Jerin Jacob
2020-03-06  9:06     ` Thomas Monjalon
2020-03-07 15:03     ` Gavin Hu
2020-03-09  7:35       ` Jerin Jacob
2020-03-09  9:23         ` Gavin Hu
2020-04-13 15:56 ` [dpdk-dev] [PATCH v2 0/2] i40e NEON vPMD optimization on aarch64 Gavin Hu
2020-04-13 15:56 ` [dpdk-dev] [PATCH v2 1/2] net/i40e: relax barrier in Tx fastpath for NEON vPMD Gavin Hu
2020-04-13 15:56 ` [dpdk-dev] [PATCH v2 2/2] net/i40e: restrict pointer aliasing " Gavin Hu
2020-04-20 14:51   ` Ferruh Yigit
2020-04-21  9:51     ` Gavin Hu
2020-04-13 16:40 ` [dpdk-dev] [PATCH v3 0/2] i40e NEON vPMD optimization on aarch64 Gavin Hu
2020-04-15  6:50   ` Ye Xiaolong
2020-04-13 16:40 ` [dpdk-dev] [PATCH v3 1/2] net/i40e: relax barrier in Tx fastpath for NEON vPMD Gavin Hu
2020-04-13 16:40 ` [dpdk-dev] [PATCH v3 2/2] net/i40e: restrict pointer aliasing " Gavin Hu

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