Re: [PATCH 0/2] perf probe fixes for ppc64le

From: Michael Ellerman
Date: Mon Apr 11 2016 - 00:41:54 EST


On Sat, 2016-04-09 at 19:12 +0530, Naveen N. Rao wrote:
>
> I suppose this boils down to the quirkiness of ABIv2. Though, in
> reality, I don't think most users will notice. As I stated above, users
> will most likely start with the disassembly or debuginfo and this patch
> ensures there are actually no surprises there.

Yeah it's unfortunate that we have to handle these two cases differently.

But I think you've chosen the right trade off.

When we are just given the name we *must not* use the global entry point,
otherwise the probes will often not hit - because most calls go to the local
entry point and skip the global entry point entirely.

When we're given a name and offset, it's less confusing if we use the global
entry point as the base for the offset calculation.

So for the concept:

Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>

I don't really know this part of the perf code enough to give you an ack for the
actual changes, I'll leave that to the perf maintainers.

cheers