Re: [PATCH 4/4] perf tools: Add support for breakpoint events inperf tools

From: Ingo Molnar
Date: Mon Nov 23 2009 - 16:25:21 EST



* Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote:

> > Using just /proc/kallsyms all we can do is find the size of a
> > variable by looking at its address and the address of the next one.
> >
> > - Arnaldo
>
> Hmm, but I worry a bit about alignment which would return us the wrong
> size.
>
> May be can we first try to get the address from /proc/kallsyms, and if
> we have dwarf, get the size from it, otherwise try some magic with
> /proc/kallsysms...

Can we extend /proc/kallsyms (or add /proc/kallsyms) to include a size
field?

Perhaps can we generate some sort of DSO-alike thing in /proc/vmlinux
(via a default-off debug option in .config), that perf could just
interpret the usual ELF way - which happens to be the symbol table of
the kernel? It would use up some RAM, but it would also be quite useful
for debugging purposes.

Ingo
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