Re: [PATCH 2/2] perf annotate: add powerpc support

On Fri, 2016-06-10 at 20:08 +0530, Naveen N. Rao wrote:

On 2016/06/10 10:36AM, Arnaldo Carvalho de Melo wrote:

quoted

Em Fri, Jun 10, 2016 at 06:32:51PM +0530, Naveen N. Rao escreveu:

quoted

Convert ins__find() to a __weak function for generic functionality,
while adding a powerpc-specific variant. We look at the function name
for branch instructions and classify the instructions to one among a
branch, a function call (branch with LR update) or a function return
(branch to LR).

How would this allow one to get a perf.data collected on a powerpc
system, transfer it to a x86-64 (or aarch64, to mention another
workstation wannabe chip) system and then try annotating it?

There was a previous discussion about this, and it involved having all
yout ppc tables available as well as other arches tables, and then
choosing which one to use based on:

	normalize_arch(thread->mg->machine->env->arch)

just like was done for support cross unwinding, see recent patch kit by
He Kuang, CCed.

Nice. This would be good to have. I will look at adding powerpc support 
for cross-architecture unwind.

However, for cross-architecture annotation, I think there will be a lot 
more dependencies since perf currently uses objdump to obtain the 
disassembly. In addition, the actual binaries will also be needed.

It's possible to build a multi-arch objdump, I don't know if it's packaged on
all distros, or if perf wants to depend on it.

cheers