USB I/O draining my userspace (Ubuntu Natty 64b)

[Yedidyah Bar-David]

On Wed, Jun 15, 2011 at 04:19:08PM +0300, Ira Abramov wrote:
> First, an appology. I added another message on the RMS fiasco only to
> find out later the threads all died out and I was committing a faux pas.
> my appologies! please ignore I posted it if at all possible.
> 
> Second, here's my problem: I have here a workstation running an Athlon
> 3700+, and part of my job is to occasionally write out an image file to
> USB universal card reader, testing the product of my builds. The writing
> takes forever (since I haven't discovered how to get dd to write out the
> sparse image to the CF card sparsely). Also, untill I moved the card
> reader to one of the backpanel ports, the write would drag my entire
> environment to a halt at the same time - even the mouse pointer gets
> stuck at some point, until dd would finish. switching from front to back
> panel and adding the oflag=dsync option solved the freַ¯ing of the
> userspace but not the horrible writing speeds.

Perhaps it uses USB1 and not 2?
Can you rmmod all *hci_ucd modules except for ehci_hcd and see what
happens?

Did you try cp (or cp --sparse=always if you really want to) and
see if it helps? I don't know of a similar option for dd.
-- 
Didi