Hi,
there were some changes in the toolchain for Power so it's time to
discuss them also on the list. There are multiple components involved,
there are defaults and additional optimized runtimes, new hardware
appearing, etc so the whole is quite complicated, but still should be
kept in sync.
The components are
- the compiler (gcc)
- the C library (glibc)
- the distro-wide default (redhat-rpm-config)
The Fedora architectures are
- ppc64 - big endian, historically supported power4/ppc970 and up,
during the time ppc64p7 subarch was added to provide Power7
(and -O3) optimized libs/binaries (about 25 packages)
- ppc64le - the new little endian variant, we have started with Power7
(and up) because it was the hardware we used in the buildsystem
The current distro defaults are (/usr/lib/rpm/redhat/rpmrc)
optflags: ppc64 %{__global_cflags} -m64
optflags: ppc64p7 %{__global_cflags} -m64 -O3 -mcpu=power7 -mtune=power7
optflags: ppc64le %{__global_cflags} -m64 -mcpu=power7 -mtune=power8
And gcc has its own defaults which can be set during the build.
The Fedora infrastructure is currently using Power8 HW for the main Koji
build system [1] to produce the binary rpms for the distrobution and we
have planned to reuse the previous Power7+ builders for COPR [2] and
Fedora Cloud.
Carlos, Florian, could you please comment on the situation?
[1]
http://ppc.koji.fedoraproject.org/
[2]
https://copr.fedoraproject.org/
Thanks
Dan