Re: [patch 00/2] improve .text size on gcc 4.0 and newer compilers

Linus Torvalds
2006-01-05T22:16:06Z

On Thu, 5 Jan 2006, Matt Mackall wrote:
>
> I think it's a mistake to interleave this data into the C source. It's
> expensive and tedious to change relative to its volatility.

I don't believe it is actually all _that_ volatile. Yes, it would be a
huge issue _initially_, but the incremental effects shouldn't be that big,
or there is something wrong with the approach.

> What I was proposing was something like, say, arch/i386/popularity.lst,
> which would simply contain a list of the most popular n% of functions
> sorted by popularity. As text, of course.

I suspect that would certainlty work for pure function-based popularity,
and yes, it has the advantage of being simple (especially for something
that ends up being almost totally separated from the compiler: if we're
using this purely to modify link scripts etc with special tools).

But what about the unlikely/likely conditional hints that we currently do
by hand? How are you going to sanely maintain a list of those without
doing that in source code?

Linus