On Tue, Jan 05, 2010 at 03:48:36PM -0800, Andrew Morton wrote: > > while writing on usb-stick via usb2.0 (tested writing about 1GB data on > > different usb-sticks) speed starts at about 14Mb/s and afterwards gets slower > > and slower (down to 700kb/s and less). Did also happen in kernel version 2.6.31 > > on another system running ubuntu with similar custom kernel, in kernel version > > 2.6.30.6 writing speed behaves normal, starts at 14Mb/s and gets just about > > 2Mb/s slower. > > While searching at google about the problem, i came across some posts which > > complained about the same behavior, but i didn't find a bug-report which > > described the issue. This is normal, and is the limit of your device. Lots of new USB flash devices are slow to write to, the initial burst of speed is the data going to the disk cache. Please verify that you are not writing small chunks at a time as well, if you use very large ones, you will hit the limit of the hardware and go much faster. I have seen this in a 4Gb write taking 7 minutes instead of 90 minutes, just by changing the block size. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
