From: Richard Zhao <linuxzsc-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> To: Alan Stern <stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org> Cc: Richard Zhao <richard.zhao-KZfg59tc24xl57MIdRCFDg@public.gmane.org>, Greg KH <gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, B29397-KZfg59tc24xl57MIdRCFDg@public.gmane.org, B20596-KZfg59tc24xl57MIdRCFDg@public.gmane.org, marex-ynQEQJNshbs@public.gmane.org, shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, alexander.shishkin-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, fabio.estevam-KZfg59tc24xl57MIdRCFDg@public.gmane.org, dong.aisheng-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, balbi-l0cyMroinI0@public.gmane.org, mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org Subject: Re: [PATCH v9 REBASE 6/9] USB: notify phy when root hub port connect change Date: Tue, 10 Jul 2012 22:53:04 +0800 [thread overview] Message-ID: <20120710145302.GA2789@richard-laptop> (raw) In-Reply-To: <Pine.LNX.4.44L0.1207101021580.1308-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> On Tue, Jul 10, 2012 at 10:24:07AM -0400, Alan Stern wrote: > On Tue, 10 Jul 2012, Richard Zhao wrote: > > > > > @@ -4037,6 +4038,13 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1, > > > > } > > > > } > > > > > > > > + if (unlikely(hcd->phy && !hdev->parent)) { > > > > > > Why is this "unlikely"? And why mark it as such, is this a "fast path" > > > that needs the compiler to know this hint to optimize things here? > > > > > > Please don't use likely() or unlikely() except in places it really is > > > needed, _and_ you have measured the difference. Have you done so in > > > this place? > > It's from a comment by Alan Stern. > > http://www.spinics.net/lists/linux-usb/msg64987.html > > That comment was made in a somewhat different context. At the time > the code was part of an interrupt handler; now it isn't. > > > Actually, for my board, it's not unlikely. But for others which don't > > have notify_connect/disconnect, it's unlikely. > > > > Because it's not unlikely for all boards, I prefer remove "unlikely". > > It's no longer a big deal one way or another. I don't care about the > "unlikely" because it's on a cold path running in process context. Go > ahead and remove it. Ok. I'll remove it. Thanks Richard > > Alan Stern > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html
WARNING: multiple messages have this Message-ID (diff)
From: linuxzsc@gmail.com (Richard Zhao) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v9 REBASE 6/9] USB: notify phy when root hub port connect change Date: Tue, 10 Jul 2012 22:53:04 +0800 [thread overview] Message-ID: <20120710145302.GA2789@richard-laptop> (raw) In-Reply-To: <Pine.LNX.4.44L0.1207101021580.1308-100000@iolanthe.rowland.org> On Tue, Jul 10, 2012 at 10:24:07AM -0400, Alan Stern wrote: > On Tue, 10 Jul 2012, Richard Zhao wrote: > > > > > @@ -4037,6 +4038,13 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1, > > > > } > > > > } > > > > > > > > + if (unlikely(hcd->phy && !hdev->parent)) { > > > > > > Why is this "unlikely"? And why mark it as such, is this a "fast path" > > > that needs the compiler to know this hint to optimize things here? > > > > > > Please don't use likely() or unlikely() except in places it really is > > > needed, _and_ you have measured the difference. Have you done so in > > > this place? > > It's from a comment by Alan Stern. > > http://www.spinics.net/lists/linux-usb/msg64987.html > > That comment was made in a somewhat different context. At the time > the code was part of an interrupt handler; now it isn't. > > > Actually, for my board, it's not unlikely. But for others which don't > > have notify_connect/disconnect, it's unlikely. > > > > Because it's not unlikely for all boards, I prefer remove "unlikely". > > It's no longer a big deal one way or another. I don't care about the > "unlikely" because it's on a cold path running in process context. Go > ahead and remove it. Ok. I'll remove it. Thanks Richard > > Alan Stern >
next prev parent reply other threads:[~2012-07-10 14:53 UTC|newest] Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-07-07 14:56 [PATCH v9 REBASE 0/9] add imx usb driver based on Greg next tree Richard Zhao 2012-07-07 14:56 ` Richard Zhao [not found] ` <1341673008-29808-1-git-send-email-richard.zhao-KZfg59tc24xl57MIdRCFDg@public.gmane.org> 2012-07-07 14:56 ` [PATCH v9 REBASE 1/9] USB: Chipidea: rename struct ci13xxx variables from udc to ci Richard Zhao 2012-07-07 14:56 ` Richard Zhao 2012-07-07 14:56 ` [PATCH v9 REBASE 2/9] USB: Chipidea: add unified ci13xxx_{add,remove}_device for platform drivers Richard Zhao 2012-07-07 14:56 ` [PATCH v9 REBASE 2/9] USB: Chipidea: add unified ci13xxx_{add, remove}_device " Richard Zhao 2012-07-07 14:56 ` [PATCH v9 REBASE 3/9] USB: Chipidea: add ci13xxx device id management Richard Zhao 2012-07-07 14:56 ` Richard Zhao 2012-07-07 14:56 ` [PATCH v9 REBASE 4/9] usb: chipidea: select USB_EHCI_ROOT_HUB_TT in USB_CHIPIDEA_HOST of Kconfig Richard Zhao 2012-07-07 14:56 ` Richard Zhao 2012-07-07 14:56 ` [PATCH v9 REBASE 5/9] usb: otg: add notify_connect/notify_disconnect callback Richard Zhao 2012-07-07 14:56 ` Richard Zhao 2012-07-07 14:56 ` [PATCH v9 REBASE 6/9] USB: notify phy when root hub port connect change Richard Zhao 2012-07-07 14:56 ` Richard Zhao [not found] ` <1341673008-29808-7-git-send-email-richard.zhao-KZfg59tc24xl57MIdRCFDg@public.gmane.org> 2012-07-09 16:57 ` Greg KH 2012-07-09 16:57 ` Greg KH [not found] ` <20120709165757.GA6024-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org> 2012-07-10 1:44 ` Richard Zhao 2012-07-10 1:44 ` Richard Zhao [not found] ` <20120710014450.GF26888-iWYTGMXpHj9ITqJhDdzsOjpauB2SiJktrE5yTffgRl4@public.gmane.org> 2012-07-10 14:24 ` Alan Stern 2012-07-10 14:24 ` Alan Stern [not found] ` <Pine.LNX.4.44L0.1207101021580.1308-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> 2012-07-10 14:53 ` Richard Zhao [this message] 2012-07-10 14:53 ` Richard Zhao 2012-07-10 3:14 ` Richard Zhao 2012-07-10 3:14 ` Richard Zhao [not found] ` <20120710031426.GG26888-iWYTGMXpHj9ITqJhDdzsOjpauB2SiJktrE5yTffgRl4@public.gmane.org> 2012-07-10 3:22 ` Marek Vasut 2012-07-10 3:22 ` Marek Vasut [not found] ` <201207100522.21162.marex-ynQEQJNshbs@public.gmane.org> 2012-07-10 11:20 ` Richard Zhao 2012-07-10 11:20 ` Richard Zhao [not found] ` <20120710112050.GH26888-iWYTGMXpHj9ITqJhDdzsOjpauB2SiJktrE5yTffgRl4@public.gmane.org> 2012-07-10 11:38 ` Marek Vasut 2012-07-10 11:38 ` Marek Vasut 2012-07-10 15:07 ` Alan Stern 2012-07-10 15:07 ` Alan Stern [not found] ` <Pine.LNX.4.44L0.1207101024110.1308-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> 2012-07-11 2:53 ` Richard Zhao 2012-07-11 2:53 ` Richard Zhao 2012-07-07 14:56 ` [PATCH v9 REBASE 7/9] usb: chipidea: permit driver bindings pass phy pointer Richard Zhao 2012-07-07 14:56 ` Richard Zhao 2012-07-07 14:56 ` [PATCH v9 REBASE 8/9] usb: otg: add basic mxs phy driver support Richard Zhao 2012-07-07 14:56 ` Richard Zhao 2012-07-07 14:56 ` [PATCH v9 REBASE 9/9] usb: chipidea: add imx platform driver Richard Zhao 2012-07-07 14:56 ` Richard Zhao 2012-07-09 17:02 ` [PATCH v9 REBASE 0/9] add imx usb driver based on Greg next tree Greg KH 2012-07-09 17:02 ` Greg KH [not found] ` <20120709170219.GA21319-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org> 2012-07-10 1:52 ` Marek Vasut 2012-07-10 1:52 ` Marek Vasut
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