Messages in this thread | | | Subject | Re: Results of actual compile printk format compression | From | Felipe Alfaro Solana <> | Date | 07 Jun 2003 07:39:39 +0200 |
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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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