From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1RISIZ-0004xO-BH for garchives@archives.gentoo.org; Mon, 24 Oct 2011 21:43:12 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id BCEC321C0D1; Mon, 24 Oct 2011 21:43:01 +0000 (UTC) Received: from mail-ww0-f53.google.com (mail-ww0-f53.google.com [74.125.82.53]) by pigeon.gentoo.org (Postfix) with ESMTP id EE19C21C021 for ; Mon, 24 Oct 2011 21:42:10 +0000 (UTC) Received: by wwi36 with SMTP id 36so8784912wwi.10 for ; Mon, 24 Oct 2011 14:42:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:from:date :x-google-sender-auth:message-id:subject:to:content-type :content-transfer-encoding; bh=lqJXoANL4rr3QIzHaAMWiGXmPBrUsE9DEOrjbmm85jA=; b=qzSvZhVMu1jaZuZrVv5OL/9S4BRAeKHVW5iFJTlb1qZCn3Q2deLVoZaFEmE22/HAHo b1R5M09XkzQVfECQb9WDMMn1YcyKxCQK5BEizlvZNfLMM6ej5A8uHooOlk/hZA4K/ubf hp/G1CjB3PgSigMdH+HfQ5F2PK8xUZ9tzvYhg= Received: by 10.227.121.74 with SMTP id g10mr1598812wbr.69.1319492530121; Mon, 24 Oct 2011 14:42:10 -0700 (PDT) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Sender: paul.hartman@gmail.com Received: by 10.227.59.193 with HTTP; Mon, 24 Oct 2011 14:41:50 -0700 (PDT) In-Reply-To: References: <4EA5D5D7.20205@binarywings.net> From: Paul Hartman Date: Mon, 24 Oct 2011 16:41:50 -0500 X-Google-Sender-Auth: FRlFa-bmzt16N1izh9Z9y0nkJpA Message-ID: Subject: Re: [gentoo-user] Re: [OT] Disappointing USB3 performance To: gentoo-user@lists.gentoo.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Archives-Salt: X-Archives-Hash: 49e9e83677f078979cbee3922e3fde90 On Mon, Oct 24, 2011 at 4:31 PM, Grant Edwards wrote: > On 2011-10-24, Florian Philipp wrote: >> Am 24.10.2011 22:02, schrieb Grant Edwards: >>> On 2011-10-24, walt wrote: >>> >>>> I just bought an add-on USB3 adapter and outboard USB3/sata docking >>>> station, and I've been comparing the performance with my old e-sata >>>> outboard docking station. =A0Not so good :( >>>> >>>> After getting some unreliable results with hdparm, I settled on >>>> copying one 3GB file from one partition of the outboard drive to >>>> another partition of the same drive. =A0These results are highly >>>> reproducible, and favor e-sata over USB3 by a large margin. >>>> >>>> Over at least six trials on each docking station I consistently get >>>> 105 seconds for USB and 84 seconds for e-sata, a 5:4 ratio in favor >>>> of e-sata. >>> >>> Not surprising. =A0Did you expect that adding a gateway device to the >>> communication path and another protocol layer on top of SATA would >>> make things faster? >>> >>>> I used the same hard disk and the same pci-e slot in the same >>>> minimally-loaded machine for all the runs, and got very consistent >>>> results every time. >>>> >>>> Basically, the USB3/sata docking station gets the same throughput as >>>> the older sata 1 drives connected to the onboard pci sata controller, >>>> which is still pretty respectable for an outboard drive, I think. >>> >>> Yep, SATA performs the same as SATA. AFAIK, eSATA and SATA are >>> identical apart from the physical specs for the connector, a few minor >>> voltage level differences (to imporove noise tolerance), and hot-plug >>> support. >> >> Normal SATA also offers hotplug. Usually works, too. > > I read somewhere that not all controllers support hotplug on > "internal" connectors, but I can't personally attest to having found > one that didn't. > >>>> So, has anyone out there done similar tests on USB3 drives yet? >>> >>> There are disk drives that talk USB3 natively and aren't just using >>> USB<->SATA gateways? >> >> Well, there is USB Attached SCSI (CONFIG_USB_UAS in the kernel). It >> supports command queuing and works for USB-2.0 and 3.0 (but has >> additional software overhead for USB-2.0). I've not yet seen a >> compatible device, though. > > Interesting. =A0Is USB3 peer to peer like SCSI and Firewire, or is it > the same master/slave poll/response scheme that has always crippled > USB? =A0Doing SCSI via a poll/response transport protocol seems like it > would lose most of the advantages of SCSI. IIRC USB3 is interrupt-driven instead of constantly polling the device.