From mboxrd@z Thu Jan 1 00:00:00 1970 From: Subject: [PATCH net-next v5 1/2] net: ethernet: mediatek: enhance RX path by reducing the frequency of the memory barrier used Date: Sat, 3 Sep 2016 17:59:26 +0800 Message-ID: <1472896767-18352-2-git-send-email-sean.wang@mediatek.com> References: <1472896767-18352-1-git-send-email-sean.wang@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , , , , , Sean Wang To: , Return-path: Received: from mailgw01.mediatek.com ([210.61.82.183]:34294 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753202AbcICJ7j (ORCPT ); Sat, 3 Sep 2016 05:59:39 -0400 In-Reply-To: <1472896767-18352-1-git-send-email-sean.wang@mediatek.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Sean Wang 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 --- 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); -- 1.9.1