diff mbox

[net-next,v5,1/2] net: ethernet: mediatek: enhance RX path by reducing the frequency of the memory barrier used

Message ID 1472896767-18352-2-git-send-email-sean.wang@mediatek.com (mailing list archive)
State New, archived
Headers show

Commit Message

Sean Wang Sept. 3, 2016, 9:59 a.m. UTC
From: Sean Wang <sean.wang@mediatek.com>

The patch makes move wmb() to outside the loop that could help
RX path handling more faster although that RX descriptors aren't
freed for DMA to use as soon as possible, but based on my experiment
and the result shows it still can reach about 943Mbpis without
performance drop that is tested based on the setup with one port
using Giga PHY and 256 RX descriptors for DMA to move.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

Comments

John Crispin Sept. 7, 2016, 6:35 a.m. UTC | #1
On 03/09/2016 11:59, sean.wang@mediatek.com wrote:
> From: Sean Wang <sean.wang@mediatek.com>
> 
> The patch makes move wmb() to outside the loop that could help
> RX path handling more faster although that RX descriptors aren't
> freed for DMA to use as soon as possible, but based on my experiment
> and the result shows it still can reach about 943Mbpis without
> performance drop that is tested based on the setup with one port
> using Giga PHY and 256 RX descriptors for DMA to move.
> 
> Signed-off-by: Sean Wang <sean.wang@mediatek.com>

gave it a quick spin on my hardware and it works well even when using
more than 1 gmac.

Acked-by: John Crispin <john@phrozen.org>

> ---
>  drivers/net/ethernet/mediatek/mtk_eth_soc.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> index 431b851..a1bdb53 100644
> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> @@ -890,13 +890,14 @@ release_desc:
>  		rxd->rxd2 = RX_DMA_PLEN0(ring->buf_size);
>  
>  		ring->calc_idx = idx;
> -		/* make sure that all changes to the dma ring are flushed before
> -		 * we continue
> -		 */
> -		wmb();
> -		mtk_w32(eth, ring->calc_idx, MTK_PRX_CRX_IDX0);
> +
>  		done++;
>  	}
> +	/* make sure that all changes to the dma ring are flushed before
> +	 * we continue
> +	 */
> +	wmb();
> +	mtk_w32(eth, ring->calc_idx, MTK_PRX_CRX_IDX0);
>  
>  	if (done < budget)
>  		mtk_w32(eth, MTK_RX_DONE_INT, MTK_PDMA_INT_STATUS);
>
diff mbox

Patch

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 431b851..a1bdb53 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -890,13 +890,14 @@  release_desc:
 		rxd->rxd2 = RX_DMA_PLEN0(ring->buf_size);
 
 		ring->calc_idx = idx;
-		/* make sure that all changes to the dma ring are flushed before
-		 * we continue
-		 */
-		wmb();
-		mtk_w32(eth, ring->calc_idx, MTK_PRX_CRX_IDX0);
+
 		done++;
 	}
+	/* make sure that all changes to the dma ring are flushed before
+	 * we continue
+	 */
+	wmb();
+	mtk_w32(eth, ring->calc_idx, MTK_PRX_CRX_IDX0);
 
 	if (done < budget)
 		mtk_w32(eth, MTK_RX_DONE_INT, MTK_PDMA_INT_STATUS);