[fedora-arm] Slow USB storage on A9 processors

Mark Salter msalter at redhat.com
Tue Sep 13 16:18:50 UTC 2011

On Tue, 2011-09-13 at 10:52 -0500, Jeffrey Bastian wrote:
> On 2011-09-13 10:18, Mark Salter wrote:
> > 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.
> Oh, you're right.  I ran bonnie++ against a USB hard drive and it shows 
> a whopping improvement!
> I've edited my blog post and added the USB hard drive numbers:
> http://jeffbastian.blogspot.com/2011/09/storage-speed-on-pandaboard-revisited.html
> > 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.
> Okay, so I should run 8 tests?
>    patch       smp      sd-card
>    patch       smp      usb-hd
>    patch       nosmp    sd-card
>    patch       nosmp    usb-hd
>    no-patch    smp      sd-card
>    no-patch    smp      usb-hd
>    no-patch    nosmp    sd-card
>    no-patch    nosmp    usb-hd

I already have a good idea what the results will look like for usb, so
just the other four with sd-card.


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