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

Ingo Molnar
2005-12-29T20:26:12Z

* Adrian Bunk <bunk@stusta.de> wrote:

> It won't be dropped on the floor indefinitely.
>
> "I do plan to look at this" means that I'd currently estimate this
> being 2.6.19 stuff.

you must be kidding ...

> Yes that's one year from now, but we need it properly analyzed and
> tested before getting it into Linus' tree, and I do really want it
> untangled from and therefore after 4k stacks.

you are really using the wrong technology for this.

look at the latency tracing patch i posted today: it includes a feature
that prints the worst-case stack footprint _as it happens_, and thus
allows the mapping of such effects in a very efficient and very
practical way. As it works on a live system, and profiles live function
traces, it goes through function pointers and irq entry nesting effects
too. We could perhaps put that into Fedora for a while and get the
worst-case footprints mapped.

in fact i've been running this feature in the -rt kernel for quite some
time, and it enabled the fixing of a couple of bad stack abusers, and it
also told us what our current worst-case stack footprint is [when 4K
stacks are enabled]: it's execve of an ELF binary.

Ingo