USB I/O performance

[Patrick O'Callaghan]

On Sun, 2009-08-30 at 19:10 -0400, Bill Davidsen wrote:
> I found that it made essentially no difference in read speed (4300k/s
> vs 4400k/s) so people should be sure they note that "write" is
> specified in the above 1st paragraph, don't overlook it!

I was careful to say I was testing write speed, but thanks for drawing
further attention to it. My specific need is to copy large files quickly
to a pendrive so I don't much care about improving read speed.

> Didn't seem to do much for write speed on a USB connected hard drive,
> so the significant benefit seems limited to write to flash. That's
> important, but for many uses there are far more reads than writes.

Same here. I did try it on my external USB hard drive (Iomega 500GB) but
I don't notice the effect. This could be because of Flash limitations in
the pendrive, but perhaps also because the hard drive has a better
processor (USB is basically a specialized packet protocol and requires a
cpu -- or at least a state machine -- at each end.)

> HINT:I wish it were a standard feature of install to a flash drive.
> Manually setting it during install is probably worth trying. Any FC11
> developers reading this? HINT!!

Good idea. It also couldn't hurt when the system is *running* from a
Live USB stick with a persistent overlay.

poc