Gentoo Archives: gentoo-user

From: Florian Philipp <lists@×××××××××××.net>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] Re: [OT] Disappointing USB3 performance
Date: Mon, 24 Oct 2011 21:18:54
Message-Id: 4EA5D5D7.20205@binarywings.net
In Reply to: [gentoo-user] Re: [OT] Disappointing USB3 performance by Grant Edwards
1 Am 24.10.2011 22:02, schrieb Grant Edwards:
2 > On 2011-10-24, walt <w41ter@×××××.com> wrote:
3 >
4 >> I just bought an add-on USB3 adapter and outboard USB3/sata docking
5 >> station, and I've been comparing the performance with my old e-sata
6 >> outboard docking station. Not so good :(
7 >>
8 >> After getting some unreliable results with hdparm, I settled on
9 >> copying one 3GB file from one partition of the outboard drive to
10 >> another partition of the same drive. These results are highly
11 >> reproducible, and favor e-sata over USB3 by a large margin.
12 >>
13 >> Over at least six trials on each docking station I consistently get
14 >> 105 seconds for USB and 84 seconds for e-sata, a 5:4 ratio in favor
15 >> of e-sata.
16 >
17 > Not surprising. Did you expect that adding a gateway device to the
18 > communication path and another protocol layer on top of SATA would
19 > make things faster?
20 >
21 >> I used the same hard disk and the same pci-e slot in the same
22 >> minimally-loaded machine for all the runs, and got very consistent
23 >> results every time.
24 >>
25 >> Basically, the USB3/sata docking station gets the same throughput as
26 >> the older sata 1 drives connected to the onboard pci sata controller,
27 >> which is still pretty respectable for an outboard drive, I think.
28 >
29 > Yep, SATA performs the same as SATA. AFAIK, eSATA and SATA are
30 > identical apart from the physical specs for the connector, a few minor
31 > voltage level differences (to imporove noise tolerance), and hot-plug
32 > support.
33 >
34
35 Normal SATA also offers hotplug. Usually works, too.
36
37 >> So, has anyone out there done similar tests on USB3 drives yet?
38 >
39 > There are disk drives that talk USB3 natively and aren't just using
40 > USB<->SATA gateways?
41 >
42
43 Well, there is USB Attached SCSI (CONFIG_USB_UAS in the kernel). It
44 supports command queuing and works for USB-2.0 and 3.0 (but has
45 additional software overhead for USB-2.0). I've not yet seen a
46 compatible device, though.
47
48 Regards,
49 Florian Philipp

Attachments

File name MIME type
signature.asc application/pgp-signature

Replies

Subject Author
[gentoo-user] Re: [OT] Disappointing USB3 performance Grant Edwards <grant.b.edwards@×××××.com>