Messages in this thread | | | Date | Mon, 26 Dec 2005 10:15:39 +0800 | From | Coywolf Qi Hunt <> | Subject | Re: Possible Bootloader Optimization in inflate (get rid of unnecessary 32k Window) |
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2005/12/22, Axel Kittenberger <axel.kernel@kittenberger.net>: > Hello, Whom do I talk to about acceptance of Patches in the Bootloader? > > I have seen, and coded once some time ago for priv. uses, do infalte the > gziped linux kernel at boottime in "arch/i386/boot/compressed/misc.c" and " > windowlib/inflate.c" the deflation algorthimn uses a 32k backtrack window. > Whenever it is full, it copies it .... into the memory. > > While this window makes a lot of sense in an userspace application like > gunzip, it does not make a lot sense in the bootloader. As userspace > application the window is flushed to a file when full. The bootloader > "flushes" it to memory (copies it in memory). That 1 time copy of the whole > kernel can be optimized away, since we do not keep track of a window since > the inflater can read what it has written right in the computer memory, while > it unpacks the kernel. > > What would the optimization be worth? > * A faster uncompressing of the kernel, since a total 1-time memcopy of the > whole kernel is been optimized away. > * I'm not sure about the size, the memory or disk footprint. If the 32k static > (!) memory array in compressed/misc.c, I don't know if it safes 32k running > memory, or 32k on-disk size. Since I don't know the indepth working of these.
Neither for saving running memory (discarded), nor on-disk size (window[WSIZE] resides in BSS).
> > Before I code this again (I know that this optimization has worked with a 2.4
I think 2.6 didn't change much in this field.
> kernel), I want to ask, would such patch be accepted? now or once ever? who > should I forward this?
"H. Peter Anvin" <hpa@zytor.com>, and akpm, and even Linus. I'd like to see your patch. It would be instructive.
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