Re: CONFIG_TINY

From: Tom Rini (trini@kernel.crashing.org)
Date: Mon Nov 04 2002 - 14:51:44 EST


On Mon, Nov 04, 2002 at 02:13:48AM +0000, Rob Landley wrote:
> On Friday 01 November 2002 14:15, Tom Rini wrote:
>
> > > Sure, and unrolling loops can cause cache misses and be slower than that
> > > jmp back in a loop. The point is this is a string, the people who think
> > > they're able to hand diddle the options can change it. And more to the
> > > point anyone who can't find a string in a makefile shouldn't be second
> > > guessing the compiler anyway.
> >
> > Yes, so why can't those who still need a few more kB after trying some
> > of the other options go and find '-O2' and replace it with '-Os' ?
>
> Because the point of CONFIG_TINY is to make the kernel smaller and this is
> something that makes the kernel smaller? (In fact telling the compiler
> "optimize for size" is one of the most OBVIOUS things to do?)
>
> I've used -Os. I've compiled dozens and dozens of packages with -Os. It has
> always saved at least a few bytes, I have yet to see it make something
> larger. And in the benchmarks I've done, the smaller code actually runs
> slightly faster. More of it fits in cache, you know.

Then we don't we always use -Os?

-- 
Tom Rini (TR1265)
http://gate.crashing.org/~trini/
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