Re: [PATCH v9] pgo: add clang's Profile Guided Optimization infrastructure

On Sat, Jun 12, 2021 at 01:56:41PM -0700, Bill Wendling wrote:

For example, Fangrui gave you numbers, and you rejected them out of
hand. I've explained to you why instrumentation is better than
sampling (at least for clang). Fangrui gave you numbers. Let's move on
to something else.

I did not dismiss them; I asked for clarification. I would like to
understand what exactly is missed by sampling based PGO data that makes
such a difference.