Re: CONFIG_TINY

Rob Landley
2002-11-05T22:50:02Z

On Tuesday 05 November 2002 19:56, Tom Rini wrote:
> On Tue, Nov 05, 2002 at 02:26:08PM -0500, Bill Davidsen wrote:
> > On Mon, 4 Nov 2002, Tom Rini wrote:
> > > On Mon, Nov 04, 2002 at 02:13:48AM +0000, Rob Landley wrote:
> > > > 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?
>
> [snip 6 good reasons]

Reasons 1 and 2 were that you can't be sure it works on all compiler versions
and all platforms until you'e tried it, which you could say about anything.

Reason 3, 5, and 6 were about performance gains, when the point of CONFIG_TINY
is, in fact, size.

Reason 4 is inertia. You are explicitly considering inertia a good reason,
then? I remember back around 1998, the argument over "-fno-strength-reduce"
which accomplished nothing whatsoever (and was in fact disabled in gcc 2.7.x
for i386) but was in the kernel compile for a long time becaue nobody could
be bothered to remove it...

> So why do we want to force it on for CONFIG_TINY?

1) The point of CONFIG_TINY is size?

2) Why is any change a "force" when you have the source code? Isn't "force"
an intentionally loaded word? I could just as easily say your objection
still boils down to "I don't want a switch that actually does something, I
want somebody to print out a to-do list and mail it to me so I can go through
the kernel by hand and remove support for floppy drives other than the actual
type I have from the legacy boot sector at the start of the kernel image."
If you want to get into loaded words.

The setting in question is a default value. CONFIG_TINY sets a lot of
defaults at once, and gives you something grep for if you don't like them. I
realise this isn't what you want, but objecting to patches because they're
completely unrelated to what you want is kind of silly.

Rob

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