On Thu, Mar 01, 2012 at 09:25:12AM +1300, Andre Renaud wrote:

Hi Russell,

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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,

Most certainly not.  We've had the data cache enabled for years and
years.  And I mean 10+ years.  We may have been lacking support on
some CPUs, but that was because of lack of contributions.

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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?

That's pure FUD.

I don't want to open a can of worms on this, and I certainly haven't
looked into the image decompressor within the Linux kernel, but from a
boot speed point of view we certainly see a significant speed
improvement switching from zImage to gzipped-Image. Do you know which
platforms include the data-cache support in the decompressor?

All.