On Mon, Jun 14, 2021 at 08:26:01AM -0700, Kees Cook wrote: > > 2. Like (1) but also keep GCOV, given proper support for attribute > > no_instrument_function would probably fix it (?). > > > > 3. Keep GCOV (and KCOV of course). Somehow extract PGO profiles from KCOV. > > > > 4. Somehow extract PGO profiles from GCOV, or modify kernel/gcov to do so. > > If there *is* a way to "combine" these, I don't think it makes sense > to do it now. PGO has users (and is expanding[1]), and trying to > optimize the design before even landing the first version seems like a > needless obstruction, and to likely not address currently undiscovered > requirements. Even if that were so (and I'm not yet convinced), the current proposal is wedded to llvm-pgo, there is no way gcc-pgo could reuse any of this code afaict, which then means they have to create yet another variant. Sorting this *before* the first version is exactly the right time. Since when are we merging code when the requirements are not clear? Just to clarify: Nacked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> For all this PGO crud.
