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* [gentoo-user] [OT] Disappointing USB3 performance
@ 2011-10-24 17:28 walt
  2011-10-24 17:45 ` Michael Mol
                   ` (4 more replies)
  0 siblings, 5 replies; 12+ messages in thread
From: walt @ 2011-10-24 17:28 UTC (permalink / raw
  To: gentoo-user

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.  Not 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.  These 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.

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.

So, has anyone out there done similar tests on USB3 drives yet?







^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [gentoo-user] [OT] Disappointing USB3 performance
  2011-10-24 17:28 [gentoo-user] [OT] Disappointing USB3 performance walt
@ 2011-10-24 17:45 ` Michael Mol
  2011-10-24 19:08 ` [gentoo-user] " Nikos Chantziaras
                   ` (3 subsequent siblings)
  4 siblings, 0 replies; 12+ messages in thread
From: Michael Mol @ 2011-10-24 17:45 UTC (permalink / raw
  To: gentoo-user

On Mon, Oct 24, 2011 at 1:28 PM, walt <w41ter@gmail.com> 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.  Not 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.  These 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.
>
> 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.
>
> So, has anyone out there done similar tests on USB3 drives yet?

I have not; I don't have a system with USB3 yet.

As far as USB3 goes, I'm more curious about host-host networking
performance. Anyone played with that? If it's reasonably reliable, I
could see 3-4 USB3 ports on three machines acting as a poor-man's
high-performance, one-hop many-many mesh network, potentially good for
network-synchronized block devices. I find Intel's Thunderbolt
interesting for similar reasons.


-- 
:wq



^ permalink raw reply	[flat|nested] 12+ messages in thread

* [gentoo-user] Re: [OT] Disappointing USB3 performance
  2011-10-24 17:28 [gentoo-user] [OT] Disappointing USB3 performance walt
  2011-10-24 17:45 ` Michael Mol
@ 2011-10-24 19:08 ` Nikos Chantziaras
  2011-10-24 19:57 ` [gentoo-user] " Paul Hartman
                   ` (2 subsequent siblings)
  4 siblings, 0 replies; 12+ messages in thread
From: Nikos Chantziaras @ 2011-10-24 19:08 UTC (permalink / raw
  To: gentoo-user

On 10/24/2011 08:28 PM, 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.  Not so good :(
>[...]
> 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.

Doesn't look surprising to me.  The USB protocol doesn't compare 
favorably with SATA.  It's good for "dumb" data transfers, but lacks 
stuff like native command queuing and DMA operations.  Most features 
supported by the actual hard disk can't be used when you connect it 
though USB.




^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [gentoo-user] [OT] Disappointing USB3 performance
  2011-10-24 17:28 [gentoo-user] [OT] Disappointing USB3 performance walt
  2011-10-24 17:45 ` Michael Mol
  2011-10-24 19:08 ` [gentoo-user] " Nikos Chantziaras
@ 2011-10-24 19:57 ` Paul Hartman
  2011-10-24 20:02 ` [gentoo-user] " Grant Edwards
  2011-10-24 23:18 ` walt
  4 siblings, 0 replies; 12+ messages in thread
From: Paul Hartman @ 2011-10-24 19:57 UTC (permalink / raw
  To: gentoo-user

On Mon, Oct 24, 2011 at 12:28 PM, walt <w41ter@gmail.com> 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.  Not so good :(

I think, generally speaking, a SATA drive plugged into a SATA port
will always be the fastest possible connection. By using a USB adapter
you're adding an additional layer of overhead to the process (the
adapter translating between USB and SATA, plus any loss of
functionality due to incompatible features like Nikos mentioned).

But if you're wonder what the speed difference should be (if the
difference you're seeing is normal or not) I can't say... I can say
USB3 is faster than USB2 for sure, but I haven't personally compared
to eSATA. :)



^ permalink raw reply	[flat|nested] 12+ messages in thread

* [gentoo-user] Re: [OT] Disappointing USB3 performance
  2011-10-24 17:28 [gentoo-user] [OT] Disappointing USB3 performance walt
                   ` (2 preceding siblings ...)
  2011-10-24 19:57 ` [gentoo-user] " Paul Hartman
@ 2011-10-24 20:02 ` Grant Edwards
  2011-10-24 21:17   ` Florian Philipp
  2011-10-24 23:18 ` walt
  4 siblings, 1 reply; 12+ messages in thread
From: Grant Edwards @ 2011-10-24 20:02 UTC (permalink / raw
  To: gentoo-user

On 2011-10-24, walt <w41ter@gmail.com> 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.  Not 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.  These 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.  Did 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.

> 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?

-- 
Grant Edwards               grant.b.edwards        Yow! How many retured
                                  at               bricklayers from FLORIDA
                              gmail.com            are out purchasing PENCIL
                                                   SHARPENERS right NOW??




^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [gentoo-user] Re: [OT] Disappointing USB3 performance
  2011-10-24 20:02 ` [gentoo-user] " Grant Edwards
@ 2011-10-24 21:17   ` Florian Philipp
  2011-10-24 21:31     ` Grant Edwards
  0 siblings, 1 reply; 12+ messages in thread
From: Florian Philipp @ 2011-10-24 21:17 UTC (permalink / raw
  To: gentoo-user

[-- Attachment #1: Type: text/plain, Size: 1997 bytes --]

Am 24.10.2011 22:02, schrieb Grant Edwards:
> On 2011-10-24, walt <w41ter@gmail.com> 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.  Not 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.  These 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.  Did 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.

>> 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.

Regards,
Florian Philipp


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^ permalink raw reply	[flat|nested] 12+ messages in thread

* [gentoo-user] Re: [OT] Disappointing USB3 performance
  2011-10-24 21:17   ` Florian Philipp
@ 2011-10-24 21:31     ` Grant Edwards
  2011-10-24 21:41       ` Paul Hartman
  0 siblings, 1 reply; 12+ messages in thread
From: Grant Edwards @ 2011-10-24 21:31 UTC (permalink / raw
  To: gentoo-user

On 2011-10-24, Florian Philipp <lists@binarywings.net> wrote:
> Am 24.10.2011 22:02, schrieb Grant Edwards:
>> On 2011-10-24, walt <w41ter@gmail.com> 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.  Not 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.  These 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.  Did 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.  Is USB3 peer to peer like SCSI and Firewire, or is it
the same master/slave poll/response scheme that has always crippled
USB?  Doing SCSI via a poll/response transport protocol seems like it
would lose most of the advantages of SCSI.

-- 
Grant Edwards               grant.b.edwards        Yow! He is the MELBA-BEING
                                  at               ... the ANGEL CAKE
                              gmail.com            ... XEROX him ... XEROX
                                                   him --




^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [gentoo-user] Re: [OT] Disappointing USB3 performance
  2011-10-24 21:31     ` Grant Edwards
@ 2011-10-24 21:41       ` Paul Hartman
  0 siblings, 0 replies; 12+ messages in thread
From: Paul Hartman @ 2011-10-24 21:41 UTC (permalink / raw
  To: gentoo-user

On Mon, Oct 24, 2011 at 4:31 PM, Grant Edwards
<grant.b.edwards@gmail.com> wrote:
> On 2011-10-24, Florian Philipp <lists@binarywings.net> wrote:
>> Am 24.10.2011 22:02, schrieb Grant Edwards:
>>> On 2011-10-24, walt <w41ter@gmail.com> 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.  Not 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.  These 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.  Did 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.  Is USB3 peer to peer like SCSI and Firewire, or is it
> the same master/slave poll/response scheme that has always crippled
> USB?  Doing 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.



^ permalink raw reply	[flat|nested] 12+ messages in thread

* [gentoo-user] Re: [OT] Disappointing USB3 performance
  2011-10-24 17:28 [gentoo-user] [OT] Disappointing USB3 performance walt
                   ` (3 preceding siblings ...)
  2011-10-24 20:02 ` [gentoo-user] " Grant Edwards
@ 2011-10-24 23:18 ` walt
  2011-10-24 23:27   ` Michael Mol
  4 siblings, 1 reply; 12+ messages in thread
From: walt @ 2011-10-24 23:18 UTC (permalink / raw
  To: gentoo-user

On 10/24/2011 10:28 AM, walt wrote:
> ...
> 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/sata over USB3/sata...

Wow, lots of great answers, guys, thanks.  Enough material to give
me lots more questions to ask you :)

Like, for example, in theory the raw bit-rate for USB3 is more than
enough to keep up with any existing consumer hard drive, right?  The
speed of usb/sata protocol translation should be very fast compared
to the speed of a spinning mechanical disk (I think?)

Now, lack of DMA is another story for hard disks, certainly.  Here's
where my ignorance of hardware limits my thinking:

AFAIK the device driver *always* sits between the disk drive and the
DMA hardware, doesn't it?

Seems to me that the USB3 driver should be fast enough to shuttle the
raw disk data (somehow) to the DMA hardware just like the pata/sata
drivers do.  It's that "somehow" that I obviously don't understand.

Where am I thinking wrong about the problem?




^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [gentoo-user] Re: [OT] Disappointing USB3 performance
  2011-10-24 23:18 ` walt
@ 2011-10-24 23:27   ` Michael Mol
  2011-10-25  0:07     ` Allan Gottlieb
  0 siblings, 1 reply; 12+ messages in thread
From: Michael Mol @ 2011-10-24 23:27 UTC (permalink / raw
  To: gentoo-user

[-- Attachment #1: Type: text/plain, Size: 1221 bytes --]

On Oct 24, 2011 7:21 PM, "walt" <w41ter@gmail.com> wrote:
>
> On 10/24/2011 10:28 AM, walt wrote:
> > ...
> > 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/sata over USB3/sata...
>
> Wow, lots of great answers, guys, thanks.  Enough material to give
> me lots more questions to ask you :)
>
> Like, for example, in theory the raw bit-rate for USB3 is more than
> enough to keep up with any existing consumer hard drive, right?  The
> speed of usb/sata protocol translation should be very fast compared
> to the speed of a spinning mechanical disk (I think?)
>
> Now, lack of DMA is another story for hard disks, certainly.  Here's
> where my ignorance of hardware limits my thinking:
>
> AFAIK the device driver *always* sits between the disk drive and the
> DMA hardware, doesn't it?

DMA means a device is told where in the system's address space it may write
to, and it writes directly to that place without further CPU involvement.
Since drivers run on the CPU, the drivr isn't a go-between.

When the CPU *is* involved in the passing of bits around, things slow down.
IIRC, that's called PIO--programmed IO.

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^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [gentoo-user] Re: [OT] Disappointing USB3 performance
  2011-10-24 23:27   ` Michael Mol
@ 2011-10-25  0:07     ` Allan Gottlieb
  2011-10-25  4:35       ` Adam Carter
  0 siblings, 1 reply; 12+ messages in thread
From: Allan Gottlieb @ 2011-10-25  0:07 UTC (permalink / raw
  To: gentoo-user

On Mon, Oct 24 2011, Michael Mol wrote:

> On Oct 24, 2011 7:21 PM, "walt" <w41ter@gmail.com> wrote:
>>
>> Now, lack of DMA is another story for hard disks, certainly.  Here's
>> where my ignorance of hardware limits my thinking:
>>
>> AFAIK the device driver *always* sits between the disk drive and the
>> DMA hardware, doesn't it?
>
> DMA means a device is told where in the system's address space it may write
> to, and it writes directly to that place without further CPU involvement.
> Since drivers run on the CPU, the drivr isn't a go-between.
>
> When the CPU *is* involved in the passing of bits around, things slow down.
> IIRC, that's called PIO--programmed IO.

Correct.  DMA stands for direct memory access; the device has direct
access to the memory.  PIO is indeed the name when the CPU acts as a go
between.

allan



^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [gentoo-user] Re: [OT] Disappointing USB3 performance
  2011-10-25  0:07     ` Allan Gottlieb
@ 2011-10-25  4:35       ` Adam Carter
  0 siblings, 0 replies; 12+ messages in thread
From: Adam Carter @ 2011-10-25  4:35 UTC (permalink / raw
  To: gentoo-user

USB does use DMA. Check the kernel source doco Documentation/usb/dma.txt



^ permalink raw reply	[flat|nested] 12+ messages in thread

end of thread, other threads:[~2011-10-25  4:36 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2011-10-24 17:28 [gentoo-user] [OT] Disappointing USB3 performance walt
2011-10-24 17:45 ` Michael Mol
2011-10-24 19:08 ` [gentoo-user] " Nikos Chantziaras
2011-10-24 19:57 ` [gentoo-user] " Paul Hartman
2011-10-24 20:02 ` [gentoo-user] " Grant Edwards
2011-10-24 21:17   ` Florian Philipp
2011-10-24 21:31     ` Grant Edwards
2011-10-24 21:41       ` Paul Hartman
2011-10-24 23:18 ` walt
2011-10-24 23:27   ` Michael Mol
2011-10-25  0:07     ` Allan Gottlieb
2011-10-25  4:35       ` Adam Carter

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