Mailinglist Archive: opensuse (1420 mails)

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[opensuse] Re: rsync causes oS 13.1 to freeze
ellanios82 wrote:
On 01/15/2014 07:58 PM, Greg Freemyer wrote:

Is your destination USB2 or USB3? If USB3, is it both the device and
the port that are USB3?

I'm not positive about this, but based on using them it seems USB2 is
a polled / non-interrupt driven technology and USB3 is interrupt
drive. That means USB2 is extremely CPU intensive to use it and the
rest of your PC suffers to a large extent.

USB3 seems far more usable and I don't see the massive overall PC
degradation when it is in use. I assume therefore it is interrupt
driven.

A quick google and review of docs implies USB2 is interrupt driven for
slow devices like keyboards / mice (HID devices), but not for fast
devices like disks.

Regardless, if you are currently using USB2 and you have a USB3 disk
handy, I would try it and see if you see the same performance impact.
___________

the device is :

Model: "Intenso External USB 3.0"
----
How old is your computer? Do you know if it came with
USB3.0 or USB2.0 ports?

(USB3 only in past 2-3 years at most).

If you really want to use your USB3 disk, from what Greg says,
you might want to invest in a USB3 card for your computer -- then the USB3
disk can use the "efficient" USB3 port instead of an inefficient USB2
port.

Note, rsync has a "--bwlimit=RATE" [try 1M as a test value, if system is too
slow, try 500K or lower, if system is fine and transfer is too slow try 2M and
go higher...?].

to tell if your system has a USB 3.0 device, an easy to use tool
looks like the usbview (usbview-2.0-2.1.3.x86_64)...

running it allows you to see what USB port your disk
is mounted on and to see the speed of the USB "Host Controller"

Mine say 12Mb/s or 480Mb/s (USB1.1 or USB2.0) -- I don't have
any USB3.0 devices, so can't tell you what they would say.


(if you need to install usbview, might try "zypper in usbview" as root.

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