Slow USB performance in Linux

[Alienwho]

For some reason, whenever i'm transfering files to/from a USB Extended memory in SUSE it only seems to transfer at 100k a second, rather than the usual 6 megabytes. Anybody know anything?

 

[drag]

You sure your not mixing up megabytes, megabits, kilobits, kilobytes?

USB 1 maxes out at 12 Megabits per second.. or about 1.5 Megabytes or about 1536 Kilobytes.

But your not going to get anywere near that in real life. More like 1000-800 Kilobytes per second would be more accurate.

So you'd never get 6 megabytes per second.. which would be 48 Megabits per second in 'networking terms'.

And that is 'USB High speed device'. A 'USB low speed device' is more likely going to provide you about 1 megabit per second. Or 1024 k or about 600-800 in practice, if that.

Not that I think your stupid or anything, but some Linux stuff can be very confusing because the programmers use the terms interchangably so you have to pay close attention to the KB versus Kb type stuff.

Then on top of that all those things are very inaccurate anyways.

Of course with the newer USB 2.0 stuff it is perfectly capable of all those speeds no problem.

Still though, of course you wouldn't notice this if it wasn't realy slow, right?


Check your kernel logs and see if you can spot what is going on. It'll give you a little bit more information to work off of.

There are two ways to do this.

The first way is to use the 'dmesg' command. This will output the 'comments' that the kernel poops out as it does its thing. So to see those you can open up a terminal and type dmesg and press enter to see what it says. Unlug and plug in the device and see what changes with the dmesg output.

Also older messages will scroll off the dmesg output. So you can look in your log file called messages. Logs files are located in /var/log

So that way maybe you can get some more information on what is going on with your usb stuff.

You can search through the dmesg output by going like this:

dmesg | less

Then you can hit the / button and then type out what your looking for and it will search through the ouputted text.

Hopefully that should help shed some light on what is going on.

 

[Alienwho]

holy crap quite the explanation.

Anyway. I am an experienced computer user...I know that generally it doesn't take me 18 minutes to transfer 75 megs from my thumbdrive to my computer...usually only a matter of seconds.

Using the same computer/same USB drive/same thumbdrive, transfering on linux takes 15 minutes whereas on windows takes 10 seconds. I'll give the info you posted a shot.

 

[bersl2]

Check that support for ECHI is built into the kernel or loaded as a module.

In fact, you might want to post the whole of the output of dmesg. It's possible that whatever kernel you use has a slightly borked USB subsystem.