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From: Slava Ovsiienko <viacheslavo@nvidia.com>
To: Ruifeng Wang <ruifeng.wang@arm.com>,
	Raslan Darawsheh <rasland@nvidia.com>,
	Matan Azrad <matan@nvidia.com>,
	Shahaf Shuler <shahafs@nvidia.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
	"jerinj@marvell.com" <jerinj@marvell.com>,
	 "nd@arm.com" <nd@arm.com>,
	"honnappa.nagarahalli@arm.com" <honnappa.nagarahalli@arm.com>
Subject: Re: [dpdk-dev] [PATCH 2/2] net/mlx5: reduce unnecessary memory access
Date: Fri, 2 Jul 2021 07:05:57 +0000	[thread overview]
Message-ID: <DM6PR12MB37536960736695A7A3911DD2DF1F9@DM6PR12MB3753.namprd12.prod.outlook.com> (raw)
In-Reply-To: <20210601083055.97261-3-ruifeng.wang@arm.com>

Hi, Ruifeng

Could we go further and implement loop inside the conditional?
Like this:
if (mlx5_mr_btree_len(&rxq->mr_ctrl.cache_bh) > 1) {
	for (i = 0; i < n; ++i) {
		void *buf_addr = elts[i]->buf_addr;

		wq[i].addr = rte_cpu_to_be_64((uintptr_t)buf_addr +
					      RTE_PKTMBUF_HEADROOM);
		wq[i].lkey = mlx5_rx_mb2mr(rxq, elts[i]);
	}
} else {
	for (i = 0; i < n; ++i) {
		void *buf_addr = elts[i]->buf_addr;

		wq[i].addr = rte_cpu_to_be_64((uintptr_t)buf_addr +
					      RTE_PKTMBUF_HEADROOM);
	}
}
What do you think?
Also,  we should check the performance on other archs is not affected.

With best regards,
Slava

> -----Original Message-----
> From: Ruifeng Wang <ruifeng.wang@arm.com>
> Sent: Tuesday, June 1, 2021 11:31
> To: Raslan Darawsheh <rasland@nvidia.com>; Matan Azrad
> <matan@nvidia.com>; Shahaf Shuler <shahafs@nvidia.com>; Slava Ovsiienko
> <viacheslavo@nvidia.com>
> Cc: dev@dpdk.org; jerinj@marvell.com; nd@arm.com;
> honnappa.nagarahalli@arm.com; Ruifeng Wang <ruifeng.wang@arm.com>
> Subject: [PATCH 2/2] net/mlx5: reduce unnecessary memory access
> 
> MR btree len is a constant during Rx replenish.
> Moved retrieve of the value out of loop to reduce data loads.
> Slight performance uplift was measured on N1SDP.
> 
> Signed-off-by: Ruifeng Wang <ruifeng.wang@arm.com>
> ---
>  drivers/net/mlx5/mlx5_rxtx_vec.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_rxtx_vec.c
> b/drivers/net/mlx5/mlx5_rxtx_vec.c
> index d5af2d91ff..fc7e2a7f41 100644
> --- a/drivers/net/mlx5/mlx5_rxtx_vec.c
> +++ b/drivers/net/mlx5/mlx5_rxtx_vec.c
> @@ -95,6 +95,7 @@ mlx5_rx_replenish_bulk_mbuf(struct mlx5_rxq_data
> *rxq)
>  	volatile struct mlx5_wqe_data_seg *wq =
>  		&((volatile struct mlx5_wqe_data_seg *)rxq->wqes)[elts_idx];
>  	unsigned int i;
> +	uint16_t btree_len;
> 
>  	if (n >= rxq->rq_repl_thresh) {
>  		MLX5_ASSERT(n >=
> MLX5_VPMD_RXQ_RPLNSH_THRESH(q_n));
> @@ -106,6 +107,8 @@ mlx5_rx_replenish_bulk_mbuf(struct mlx5_rxq_data
> *rxq)
>  			rxq->stats.rx_nombuf += n;
>  			return;
>  		}
> +
> +		btree_len = mlx5_mr_btree_len(&rxq->mr_ctrl.cache_bh);
>  		for (i = 0; i < n; ++i) {
>  			void *buf_addr;
> 
> @@ -119,8 +122,7 @@ mlx5_rx_replenish_bulk_mbuf(struct mlx5_rxq_data
> *rxq)
>  			wq[i].addr = rte_cpu_to_be_64((uintptr_t)buf_addr +
> 
> RTE_PKTMBUF_HEADROOM);
>  			/* If there's a single MR, no need to replace LKey. */
> -			if (unlikely(mlx5_mr_btree_len(&rxq-
> >mr_ctrl.cache_bh)
> -				     > 1))
> +			if (unlikely(btree_len > 1))
>  				wq[i].lkey = mlx5_rx_mb2mr(rxq, elts[i]);
>  		}
>  		rxq->rq_ci += n;
> --
> 2.25.1


  reply	other threads:[~2021-07-02  7:06 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-01  8:30 [dpdk-dev] [PATCH 0/2] MLX5 PMD tuning Ruifeng Wang
2021-06-01  8:30 ` [dpdk-dev] [PATCH 1/2] net/mlx5: remove redundant operations Ruifeng Wang
2021-07-02  8:12   ` Slava Ovsiienko
2021-07-02 10:30     ` Ruifeng Wang
2021-07-05 10:01       ` Slava Ovsiienko
2021-07-07  8:00         ` Ruifeng Wang
2021-06-01  8:30 ` [dpdk-dev] [PATCH 2/2] net/mlx5: reduce unnecessary memory access Ruifeng Wang
2021-07-02  7:05   ` Slava Ovsiienko [this message]
2021-07-02  7:28     ` Ruifeng Wang
2021-06-30  7:22 ` [dpdk-dev] [PATCH 0/2] MLX5 PMD tuning Ruifeng Wang
2021-07-07  9:03 ` [dpdk-dev] [PATCH v2 " Ruifeng Wang
2021-07-07  9:03   ` [dpdk-dev] [PATCH v2 1/2] net/mlx5: remove redundant operations Ruifeng Wang
2021-07-12 15:31     ` Slava Ovsiienko
2021-07-07  9:03   ` [dpdk-dev] [PATCH v2 2/2] net/mlx5: reduce unnecessary memory access Ruifeng Wang
2021-07-12 15:33     ` Slava Ovsiienko
2021-07-13  9:32   ` [dpdk-dev] [PATCH v2 0/2] MLX5 PMD tuning Raslan Darawsheh

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