On Thu, Mar 3, 2022 at 8:16 AM John Paul Adrian Glaubitz <[email protected]> wrote: > > Hello! > > On 3/2/22 21:14, Otto Kekäläinen wrote: > > A recent build regression on ppc64el is preventing a new MariaDB version > > from migrating from unstable to testing. > > > > Could any experts on this list help out? > > I don't know where this code is coming from, but this is definitely wrong: > > > https://salsa.debian.org/mariadb-team/mariadb-server/-/blob/debian/latest/mysys/CMakeLists.txt#L145 > > The code is forcing compiler flags based on the architecture and thus > overriding the > baseline. This is a baseline violation and not allowed per Debian Policy. > > And, in particular, it violates the baseline of the ppc64 port which is using > POWER5, > not POWER8.
John, The selective CFLAGS on specific files are there to enable optimizations in certain functions. Elsewhere in the code there is runtime detection made of the VSX/vpmsum to actually use the code. So for POWER5 it should be there but dormant. Likewise for the bug here. We've got a htmxlintrin.h header insisting on the -mhtm, backed up the compiler that doesn't define the __builtin_tbegin builtins without the cflags. We use the htm target function attribute to compile specific functions that use it, however the use of instructions is still behind a runtime check. We can't include the header check inside a function, otherwise we are defining an inline function within a function. My work in progress fix is along these lines: https://github.com/MariaDB/server/commit/6df3911b61ba669285c08b1456276217c7881292 note just below the standard view of this commit at the bottom, there is transactional_lock_enabled that does runtime detection. But it's still failing (https://buildbot.mariadb.org/#/grid?branch=bb-10.6-danielblack-MDEV-27936-ppc64-htm-build-fail , for sid only, and only recent (https://buildbot.mariadb.org/#/grid?branch=10.6)), proving sid is true to its name. If this still violates the policy, I'd like to know now so I can implement solutions that drop support for ppc64 POWER5+ and support hardware like ppc64le, POWER8+ that we actually do have hardware for and can support.
