Re: [PATCH net-next v5 1/2] net: ethernet: mediatek: enhance RX path by reducing the frequency of the memory barrier used
From: John Crispin <john@phrozen.org>
Date: 2016-09-07 06:35:39
Also in:
linux-mediatek
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>
quoted hunk ↗ jump to hunk
--- 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);