On Tue, 5 Jun 2007, manoj mathai wrote: > hi, > > I am Manoj from Mumbai, India. I am having problems with my USB 2.0 > pen drive on linux. i am having the same problem on almost all linux > distros i tried and i think it might have something to do with the > linux usb drivers. i am not sure though, > please correct me if i am wrong. i don't mind a detailed explanation > as to why this is happening :). > > I have a 2 GB USB pen drive. while writing large amount of data (~2GB) > to the pen drive , the kernel load( as shown by gnome system monitor > applet) shoots up to around 6 to 7, the entire gui becomes very > unresponsive and the system feels laggy.
Can you find out which process is using a lot of CPU time? Or do you think the problem is simply that too much memory is being used for buffers? > i have 1 GB Ram. the mem > usage during the transfer is quite high and eats almost my entire Ram. > my home machine is a gentoo on amd64. i tried it on ubuntu, mandriva > and fedora i386. all had the same issues. Also, sometimes, it takes a > lot of time (about 2-3 minutes sometimes) to unmount the pen drive. > apparently, some amount of the data to be transferred is cached and it > is flushed to the device only when i give the umount command. i am > using default I/O scheduler - "CFQ" and pre-emption model - "voluntary > kernel preemption(Desktop)". This is not a USB issue. The block and filesystem layers are responsible for deciding how much memory to use for file I/O buffers. When you say it takes a long time to unmount the pen drive, maybe what you really mean is that the file transfer program exits too quickly. If it did not terminate so soon, then you would realize that the time was required for transferring the data and you wouldn't think it was in any way connected with unmounting. What you need to do is reduce the amount of memory used for I/O buffers. However I don't know how you can control it. Maybe people on LKML can provide some advice. Alan Stern ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
