On 08/01/2021 10:48, Fabian Arrotin wrote: > On 08/01/2021 10:15, Florian Weimer wrote: >> * Fabian Arrotin: >> >>> Thanks a lot for the announce, really appreciated to be aware of what's >>> coming . >>> I'd (myself) like to see some kind of announces being sent on the public >>> list so that everybody can follow what's being worked on and so what to >>> expect in Stream packages (as of course there is no official public >>> Release Notes -yet- , appearing for RHEL, so downstream) >> >> I'm going to let others comment on that. >> >>> Now back to the x86 cpu infra : does that mean that to *build* Stream >>> packages (like gblic) we need at least a minimum instructions set in the >>> CPU (builder side that is) ? >> >> glibc itself continues to use IFUNCs on x86-64 to select optimized >> function implementations, based on CPU capabilities. This means that >> baseline x86-64 support remains sufficient for building the glibc >> package. >> >> I can image that in the future, there will be some packages which build >> shared objects for x86-64-v3 (in addition to baseline x86-64, with >> run-time selection later), and which test all implementations at build >> time. In such a scenario, the builders would have to support x86-64-v3. >> >> In related news, we plan to build CentOS Stream 9 with a x86-64-v2 >> baseline: >> >> Building Red Hat Enterprise Linux 9 for the x86-64-v2 microarchitecture level >> <https://developers.redhat.com/blog/2021/01/05/building-red-hat-enterprise-linux-9-for-the-x86-64-v2-microarchitecture-level/> >> > > Thanks a lot, that's exactly the kind of information I wish we had when > we started to build the new infra for Stream 9 .... now to see if what > deployed as hardware for this is enough :) > So if we have to start with x86-64-v2 (and eventually x86-64-v3 later one for some pkgs), I just checked all (normally) needed cpu flags and we're so "covered" .. : for flag in sse3 sse4_2 popcnt cx16 avx2 movbe; do egrep -q ${flag} /proc/cpuinfo && echo "Flag ${flag} present !" || echo "Flag ${flag} MISSING" ; done Flag sse3 present ! Flag sse4_2 present ! Flag popcnt present ! Flag cx16 present ! Flag avx2 present ! Flag movbe present ! I was in 'panic mode' for some minutes until I was able to confirm that what we have should work .. ;-) -- Fabian Arrotin The CentOS Project | https://www.centos.org gpg key: 17F3B7A1 | twitter: @arrfab