Re: [RFC 00/15] perf: Add backtrace post dwarf unwind

[Ulrich Drepper]

On Fri, Mar 30, 2012 at 08:10, Masami Hiramatsu
<masami.hiramatsu.pt@xxxxxxxxxxx> wrote:
> Right, almost all function arguments are passed by register on x86-64.
> Hmm, this might be useful because it can trace function register-arguments
> in user-space applications... even though it causes interruption on every
> sampling calls...

You only have to do this for the first call frame and only if the
breakpoint is at the first instruction of the function.

Otherwise the register content can of course already be destroyed.

Given this, is it really worth it?  For instance, for any backtrace
from the breakpoint in kernel there is nothing at all you gain from
recording the register content.
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