From patchwork Thu Apr 8 06:44:59 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bryan Wu X-Patchwork-Id: 49698 X-Patchwork-Delegate: apw@canonical.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from chlorine.canonical.com (chlorine.canonical.com [91.189.94.204]) by ozlabs.org (Postfix) with ESMTP id A1553B7C8E for ; Thu, 8 Apr 2010 16:46:29 +1000 (EST) Received: from localhost ([127.0.0.1] helo=chlorine.canonical.com) by chlorine.canonical.com with esmtp (Exim 4.69) (envelope-from ) id 1NzlVQ-00043B-F3; Thu, 08 Apr 2010 07:46:24 +0100 Received: from adelie.canonical.com ([91.189.90.139]) by chlorine.canonical.com with esmtp (Exim 4.69) (envelope-from ) id 1NzlVO-000432-BW for kernel-team@lists.ubuntu.com; Thu, 08 Apr 2010 07:46:22 +0100 Received: from hutte.canonical.com ([91.189.90.181]) by adelie.canonical.com with esmtp (Exim 4.69 #1 (Debian)) id 1NzlVO-0003ta-8z for ; Thu, 08 Apr 2010 07:46:22 +0100 Received: from [58.33.177.64] (helo=canonical.com) by hutte.canonical.com with esmtpsa (TLS-1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.69) (envelope-from ) id 1NzlVL-0004jq-De for kernel-team@lists.ubuntu.com; Thu, 08 Apr 2010 07:46:22 +0100 From: Bryan Wu To: kernel-team@lists.ubuntu.com Subject: [PATCH 2/2] netdev/fec: fix performance impact from mdio poll operation Date: Thu, 8 Apr 2010 14:44:59 +0800 Message-Id: <1270709099-9303-2-git-send-email-bryan.wu@canonical.com> X-Mailer: git-send-email 1.7.0.1 In-Reply-To: <1270709099-9303-1-git-send-email-bryan.wu@canonical.com> References: <1270709099-9303-1-git-send-email-bryan.wu@canonical.com> X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.9 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: kernel-team-bounces@lists.ubuntu.com Errors-To: kernel-team-bounces@lists.ubuntu.com BugLink: http://bugs.launchpad.net/bugs/546649 BugLink: http://bugs.launchpad.net/bugs/457878 After introducing phylib supporting, users experienced performace drop. That is because of the mdio polling operation of phylib. Use msleep to replace the busy waiting cpu_relax() and remove the warning message. Signed-off-by: Bryan Wu --- drivers/net/fec.c | 45 +++++++++++++++++++++------------------------ 1 files changed, 21 insertions(+), 24 deletions(-) diff --git a/drivers/net/fec.c b/drivers/net/fec.c index 53240d3..2280373 100644 --- a/drivers/net/fec.c +++ b/drivers/net/fec.c @@ -216,7 +216,7 @@ static void fec_stop(struct net_device *dev); #define FEC_MMFR_TA (2 << 16) #define FEC_MMFR_DATA(v) (v & 0xffff) -#define FEC_MII_TIMEOUT 10000 +#define FEC_MII_TIMEOUT 10 /* Transmitter timeout */ #define TX_TIMEOUT (2 * HZ) @@ -624,13 +624,29 @@ spin_unlock: /* * NOTE: a MII transaction is during around 25 us, so polling it... */ -static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum) +static int fec_enet_mdio_poll(struct fec_enet_private *fep) { - struct fec_enet_private *fep = bus->priv; int timeout = FEC_MII_TIMEOUT; fep->mii_timeout = 0; + /* wait for end of transfer */ + while (!(readl(fep->hwp + FEC_IEVENT) & FEC_ENET_MII)) { + msleep(1); + if (timeout-- < 0) { + fep->mii_timeout = 1; + break; + } + } + + return 0; +} + +static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum) +{ + struct fec_enet_private *fep = bus->priv; + + /* clear MII end of transfer bit*/ writel(FEC_ENET_MII, fep->hwp + FEC_IEVENT); @@ -639,15 +655,7 @@ static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum) FEC_MMFR_PA(mii_id) | FEC_MMFR_RA(regnum) | FEC_MMFR_TA, fep->hwp + FEC_MII_DATA); - /* wait for end of transfer */ - while (!(readl(fep->hwp + FEC_IEVENT) & FEC_ENET_MII)) { - cpu_relax(); - if (timeout-- < 0) { - fep->mii_timeout = 1; - printk(KERN_ERR "FEC: MDIO read timeout\n"); - return -ETIMEDOUT; - } - } + fec_enet_mdio_poll(fep); /* return value */ return FEC_MMFR_DATA(readl(fep->hwp + FEC_MII_DATA)); @@ -657,9 +665,6 @@ static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum, u16 value) { struct fec_enet_private *fep = bus->priv; - int timeout = FEC_MII_TIMEOUT; - - fep->mii_timeout = 0; /* clear MII end of transfer bit*/ writel(FEC_ENET_MII, fep->hwp + FEC_IEVENT); @@ -670,15 +675,7 @@ static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum, FEC_MMFR_TA | FEC_MMFR_DATA(value), fep->hwp + FEC_MII_DATA); - /* wait for end of transfer */ - while (!(readl(fep->hwp + FEC_IEVENT) & FEC_ENET_MII)) { - cpu_relax(); - if (timeout-- < 0) { - fep->mii_timeout = 1; - printk(KERN_ERR "FEC: MDIO write timeout\n"); - return -ETIMEDOUT; - } - } + fec_enet_mdio_poll(fep); return 0; }