Re: XZ compression for the initramfs
On Sun, Jan 03, 2016 at 11:04:22AM -0500, Alan Corey wrote:
> What about the RAM usage? I can't even use it often on my devio.us
> account because there's shared RAM with other users. Seems like an
> embedded system might have a problem with that too.
Well good question. Seems for max compression, compression can take up to 674MB while decompression will then take 65MB. For lower (like the default) compression it takes less. I don't think max compression is typically used with xz, and shouldn't be.
With the default -6, it uses 94MB to compress and 9MB to decompress.
Also the manual says it does not make sense to use a dictinary size
bigger than the input file, and -6 uses 8MB, while -7 uses 16MB, -8 32MB
and -9 64MB. So unless dealing with an initrd that is that big before
compression, it is just a waste of ram and cpu time to use higher than -6.
--
Len Sorensen
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