On Sun, Aug 03, 2025 at 05:27:01PM -0500, Segher Boessenkool wrote: > You are replacing a known-working target implementation by a lower > performance generic implementation.
That's probably correct, though FWIW there have been quite a few cases where optimized assembly code in the kernel actually turned out to be slower than the C code. (That primarily happens when the assembly code doesn't take advantage of any special CPU features, which was the case for this PowerPC code.) I don't have PowerPC hardware to check the exact performance differential here, but IMO even if there was a slowdown the factors still weigh strongly in favor of retiring this. > But is that one known-working at all? Does it come with tests? Was > it tested to have the same outputs as the existing thing, maybe? Just > on a few inputs maybe. Of course. Patch 7 adds a KUnit test suite for MD5, and there are still the older tests in crypto/testmgr.c. And of course generic code is much easier to test than arch-specific code. So not only is it tested, but the test coverage is much better than it was before. - Eric
