From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sean Wang Subject: [PATCH v2 4/5] net: ethernet: mediatek: enhance RX path by reducing the frequency of the memory barrier used Date: Tue, 16 Aug 2016 01:51:25 +0800 Message-ID: <1471283487-24113-5-git-send-email-sean.wang@mediatek.com> References: <1471283487-24113-1-git-send-email-sean.wang@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , , , , Sean Wang To: , Return-path: Received: from mailgw02.mediatek.com ([210.61.82.184]:27442 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752924AbcHORvg (ORCPT ); Mon, 15 Aug 2016 13:51:36 -0400 In-Reply-To: <1471283487-24113-1-git-send-email-sean.wang@mediatek.com> Sender: netdev-owner@vger.kernel.org List-ID: The patch makes moving 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 show it still can reach about 943Mbpis without performance drop that is tested based on the setup with one port using gigaphy 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 b782330..53e24c1 100644 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c @@ -893,14 +893,15 @@ 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_QRX_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_QRX_CRX_IDX0); + if (done < budget) mtk_w32(eth, MTK_RX_DONE_INT, MTK_QMTK_INT_STATUS); -- 1.7.9.5