Re: [patch 1/4] Linux Kernel Markers - Architecture Independent Code

Frank Ch. Eigler
2007-10-26T14:30:45Z

Hi -

On Thu, Oct 25, 2007 at 03:17:22PM -0400, Mathieu Desnoyers wrote:
> [...]
> Since gcc is required to build the systemtap probes on the development
> marchine, I don't see why it would be much harder to also require prople
> to install drawf ? Or maybe the "crash" tool ?

The crash tool requires the dwarf data to work. The dwarf data for an
entire kernel (including all the modules) is on the order of hundreds
of megabytes. The symbol & marker list would be one thousandth the
size. You can see the deployment attractiveness of the latter.

> I guess you must already need to extract the symbols for your kprobes.
> Do you use kallsyms for this?

Nope. /proc/kallsyms is a another run-time-only source of data, and
so is not applicable for off-line (ahead-of-time) mapping.

> I would rather prefer not to implement superfluous built-time data
> extraction in the kernel build system just to make userspace
> simpler. [...]

It is not superfluous, as it would solve a real distribution problem.

- FChE