From patchwork Tue Aug 16 06:17:13 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Wang X-Patchwork-Id: 9282645 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id BE9CF60839 for ; Tue, 16 Aug 2016 06:17:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B0E3F288A1 for ; Tue, 16 Aug 2016 06:17:46 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A544C289A6; Tue, 16 Aug 2016 06:17:46 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id D76822888E for ; Tue, 16 Aug 2016 06:17:45 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bZXh2-0001Y6-TC; Tue, 16 Aug 2016 06:17:44 +0000 Received: from [210.61.82.184] (helo=mailgw02.mediatek.com) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bZXgz-0001Ue-VQ for linux-mediatek@lists.infradead.org; Tue, 16 Aug 2016 06:17:42 +0000 Received: from mtkhts09.mediatek.inc [(172.21.101.70)] by mailgw02.mediatek.com (envelope-from ) (mhqrelay.mediatek.com ESMTP with TLS) with ESMTP id 1312568591; Tue, 16 Aug 2016 14:17:17 +0800 Received: from mtkswgap22.mediatek.inc (172.21.77.33) by mtkhts09.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 14.3.266.1; Tue, 16 Aug 2016 14:17:16 +0800 From: Sean Wang To: , Subject: [PATCH net-next v3 1/2] net: ethernet: mediatek: enhance RX path by reducing the frequency of the memory barrier used Date: Tue, 16 Aug 2016 14:17:13 +0800 Message-ID: <1471328235-16724-2-git-send-email-sean.wang@mediatek.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1471328235-16724-1-git-send-email-sean.wang@mediatek.com> References: <1471328235-16724-1-git-send-email-sean.wang@mediatek.com> MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160815_231742_242241_3D1E5C5B X-CRM114-Status: GOOD ( 10.35 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: netdev@vger.kernel.org, nbd@openwrt.org, Sean Wang , linux-mediatek@lists.infradead.org, keyhaede@gmail.com Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+patchwork-linux-mediatek=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP 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 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 b782330..589ff50 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);