Andre Renaud wrote at Wednesday, February 29, 2012 1:12 PM:

On 01/03/12 08:59, Stephen Warren wrote:

quoted

Uwe Kleine-König wrote at Wednesday, February 29, 2012 12:44 PM:
...

quoted

If you want to give incentive for U-Boot to improve, drop the target
today. And note that at least people caring about boot time must not use
the kernel's uImage target anyhow.

If you enable the new config option in this patch, then the performance
issue is solved; U-Boot doesn't copy the kernel image any more, and the
kernel decompressor can write directly to the appropriate location without
moving the image first (assuming your board boot script loads the uImage
to a non-conflicting address).

I may have missed part of this, but isn't one of the points regarding
this that the zImage decompressor always runs with data cache disabled,
resulting in a slow decompress, where as if the U-Boot decompressor is
used (ie, gzipping the Image, and telling U-Boot to decompress), then it
can run with caches enabled, improving boot speed?

Thus the relocation issue is not really the speed hit, rather it is the
image decompression.

OK, there probably are multiple different issues affecting the performance,
and this patch only affects the one that applies once you've decided to use
uImage to wrap a zImage in the first place.

-- 
nvpublic