[PATCH] cafe_nand: remove busy-wait loop

Tomeu Vizoso tomeu at sugarlabs.org
Tue Dec 9 12:14:02 EST 2008


On Tue, Dec 9, 2008 at 6:05 PM, Mitch Bradley <wmb at laptop.org> wrote:
> Nice!
>
> One quick test, for starters, is to do some file accesses to large files
> (dd or tar or whatever) and use the "time" command to look at the system
> and user times.  With the patch, the system time should drop to a
> fraction of the real time.

Wow! This should apply as well to writes?

I reported some time ago that downloads from the LAN were limited by
cpu time, but I think to remember that it was due to the
autocompression.

Regards,

Tomeu

> Daniel Drake wrote:
>> This patch enables interrupts for DMA and command completion events, and
>> uses them to determine when commands and transfers have completed.
>>
>> This avoids a busy-wait loop which was a waste of CPU time.
>>
>> Signed-off-by: Daniel Drake <dsd at laptop.org>
>>
>> ---
>> Where do we go with this? Who's adventurous enough to test it? Dare we
>> put it in joyride? Any suggestions for how to measure performance
>> difference?
>>
>
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