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

Tue Sep 19 18:48:57 UTC 2006

Phil Meyer wrote:
> 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.

Yes I am sure. It supports many different card types. With compactflash 
cards it runs extremely fast.

Here is simple benchmark: "file" is 50MB big:

# time { cp file /media/disk/; sync; }

real    0m30.390s
user    0m0.004s
sys     0m0.256s

This seems to be 1.6 MB/Sec, which is the speed of  USB-1 devices. I am 
sure though, that it is a USB-2 device.
According to a german wikipedia page 
(http://de.wikipedia.org/wiki/Memorystick), the actual tranfer rate 
isn't higher than 2MB/s for MS Pro Duo cards, though they are marked 
with 20MB/s.

>
> Some USB busses have trouble with mixing USB 1 and USB 2 devices.  Is 
> there any other USB device connected to the system?
>
nope, no problems.

> 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?

Each device is connected to it's "own" bus:

# lsusb
Bus 002 Device 002: ID 046d:c506 Logitech, Inc. MX-700 Cordless Mouse 
Receiver
Bus 002 Device 001: ID 0000:0000
Bus 003 Device 004: ID 058f:6362 Alcor Micro Corp.
Bus 003 Device 001: ID 0000:0000
Bus 001 Device 001: ID 0000:0000

>>
>> 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?

Here's the output from "tail -f /var/log/messages" after I have plugged 
in the device:

Sep 19 20:23:19 machine kernel: usb 3-6: new high speed USB device using 
ehci_hcd a nd address 4
Sep 19 20:23:19 machine kernel: usb 3-6: configuration #1 chosen from 1 
choice
Sep 19 20:23:19 machine kernel: scsi3 : SCSI emulation for USB Mass 
Storage devices
Sep 19 20:23:24 machine kernel:   Vendor: Generic   Model: USB SD 
Reader     Rev: 1 .00
Sep 19 20:23:24 machine kernel:   Type:   
Direct-Access                      ANSI S CSI revision: 00
Sep 19 20:23:24 machine kernel: sd 3:0:0:0: Attached scsi removable disk sdb
Sep 19 20:23:24 machine kernel: sd 3:0:0:0: Attached scsi generic sg1 type 0
Sep 19 20:23:24 machine kernel:   Vendor: Generic   Model: USB CF 
Reader     Rev: 1 .01
Sep 19 20:23:24 machine kernel:   Type:   
Direct-Access                      ANSI S CSI revision: 00
Sep 19 20:23:24 machine kernel: sd 3:0:0:1: Attached scsi removable disk sdc
Sep 19 20:23:24 machine kernel: sd 3:0:0:1: Attached scsi generic sg2 type 0
Sep 19 20:23:24 machine kernel:   Vendor: Generic   Model: USB SM 
Reader     Rev: 1 .02
Sep 19 20:23:24 machine kernel:   Type:   
Direct-Access                      ANSI S CSI revision: 00
Sep 19 20:23:24 machine kernel: sd 3:0:0:2: Attached scsi removable disk sdd
Sep 19 20:23:24 machine kernel: sd 3:0:0:2: Attached scsi generic sg3 type 0
Sep 19 20:23:24 machine kernel:   Vendor: Generic   Model: USB MS 
Reader     Rev: 1 .03
Sep 19 20:23:24 machine kernel:   Type:   
Direct-Access                      ANSI S CSI revision: 00
Sep 19 20:23:24 machine kernel: sd 3:0:0:3: Attached scsi removable disk sde
Sep 19 20:23:24 machine kernel: sd 3:0:0:3: Attached scsi generic sg4 type 0

>
> 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.
>
>

If you say, that there are bugs around, I'm sure that this issue will be 
fixed soon.

In my case I have to count to 500, as I am copying hundreds of MBs :-)

Thanks for you hints!!

greets

Boris