[fedora-arm] Slow USB storage on A9 processors

[Mark Salter]

On Tue, 2011-09-13 at 09:49 -0500, Jeffrey Bastian wrote:
> On 2011-09-12 13:24, David Marlin wrote:
> > I'm glad you were able to find the problem. This kernel probably lacks
> > the patch to handle the persistent MAC address. It does, however, have
> > support for Flattened Device Tree, and a patch to read a MAC address
> > from the device tree, which could be used to make the MAC address
> > persistent.
> 
> Great!  I'll give the FDT a try next.
> 
> 
> >> It's time for another round of bonnie++
> >
> > I have resync'd the xpfa yum repo for f13 and verified
> > kernel-omap-2.6.40.3-2.02.fc13.armv7l.rpm is there. I updated the panda
> > to 2.6.40.3-2.02 and it boots and runs without issue.
> >
> > This version includes Mark Salter's patch, so you'll want it before
> > doing the USB storage performance testing.
> 
> 
> The bonnie++ results were mixed.  Sequential reads showed a bit of a 
> boost, but writes and random seeks took a huge hit.  I published the 
> numbers on my blog:
> http://jeffbastian.blogspot.com/2011/09/storage-speed-on-pandaboard-revisited.html

These numbers are for SD card in an mmc slot, right? I wouldn't expect
the patch to the USB EHCI driver to have any effect on SD card speed.
The big write performance hits are worrisome, though. I'd be good to
test on one kernel version with and without the patch just to make sure.
Also comparing SD performance with and without nosmp passed on cmdline
would be interesting.

--Mark