On Sat, 2003-06-07 at 00:52, Timothy Miller wrote:
> Just a quick note...
>
> Although my experiments with kernel printk format string compression
> have reported estimated shrinkage, this is the first time I have been
> able to compile a whole kernel with the compression filter.
>
> These results come from doing an allyesconfig of 2.5.68 and then weeding
> out anything that didn't build. One program extracts strings from
> preprocessor output, a second program determines how the strings will be
> encoded, and the third makes substitutions during a kernel compile.
>
> The uncompressed compile resulted in a kernel image of 24011892 bytes.
> The resulting image with format strings compressed is 23904708 bytes
> which is a shrinkage of 107184 bytes. Subtracting out an estimate of 3K
> for the dictionary and necessary modifications to printk, that results
> in a reduction of something like 104112 which is 4% of the original
> kernel size.
>
> That may not seem like a lot, but if you consider only the printk
> strings themselves, they are compressed to less than 50% of their
> original size (counting the dictionary but not printk code mods).
>
> So, I ask... is this a useful savings? Is there any chance anyone would
> bother to increase their compile time by a factor of 5 in order to shave
> off 4% or 100k bytes?
>
> (Not to mention that allyesconfig is a very unrealistic scenario.)
Sincerely, with machines ranging 512MB of memory, 100KB of memory saving
is just so little, that factoring kernel compilation by 5 is something
I'm not willing to take.
However, it could be useful to include that feature for memory
constrained systems, like embedded ones, and allow enabling it at
compile/configure time.
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This archive was generated by hypermail 2b29 : Sat Jun 07 2003 - 22:00:32 EST