FC5: High system load when copying data to slow USB media

[Phil Meyer]

Boris Glawe wrote:
> Hi,
>
> I have a problem with my 2GB Memory Stick Pro Duo Card. The card 
> itself is an orginal MemoryStick PRO Duo from Sony.
>
> I am using this card in my cell phone. The phone is a Sony Ericsson 
> W810i, which is capable to appear as an usb mass storage device. I 
> also have an USB 2.0 card reader. The problem described below happens 
> with both the card reader and the cell phone.
Are you certain that it is in fact a USB 2 card reader?  You should be 
getting at least 5MB/sec transfer rates from that card, whether in the 
phone or on the reader.

Some USB busses have trouble with mixing USB 1 and USB 2 devices.  Is 
there any other USB device connected to the system?

Some mother boards use the same USB bus for fron and rear connections.  
That means that a USB 1 device connected to the front, and interfere 
with a USB device plugged into the rear.

Lets say you have an old USB mouse plugged in.  Maybe its old enough to 
be a USB 1 device.  It is possible to have the symptoms you describe in 
this case.  The USB 1 mouse will interfere with a USB 2 disk drive at 
the hardware layer.  It will cause the entire USB bus to drop to USB 1 
speeds.

In order to help prevent that, the USB 1.1 specification allows a slow 
device to advertise itself as a fast device.  This does not always work.

# yum install usbutils
# lsusb

Is there more than one USB bus?  Is the card reader or phone on a bus by 
itself?
>
> My problem is, that copying large amounts of data (a few hundred MBs, 
> for example) to that device causes the system load to increase to 
> almost 100% and, under certain circumstances, to lock my desktop from 
> time to time during the copying process. It is normal that copying 
> takes very long, as the card itself is very slow in writing, but the 
> high system load in combination with the lack of responsiveness of the 
> whole system seems to be a bug!?
This really sounds like a conflict.
It can be caused by an interrupt conflict, and/or a device conflict.
Plug the card in and:
# dmesg | tail -30
What do you see?  Is the system quick to recognize the drive?  Any errors?

It is true that the latest kernels in FC5 are having flush on unmount 
problems with removable media.  The last working kernel was the last 
2.6.16 kernel (2133).  There are currently several USB related kernel 
bugs in the 2.6.17 kernels.  Enough to cover the symptoms you see when 
you try to unmount.  Many folks are seeing that.

However, if we can figure out what is happening in regards to your 
system thrashing during writes, the too slow flush at unmount will be 
eased a bit.

It is common practice for me to 'count to 10' now days before pulling 
out a memory card after a umount.  I currently work with CF and SD cards 
nearly every day.  I feel your pain.