Building on ubuntu gets stuck due to insufficient (?) guards for AVX512 code

Hi,

For me once in a while the ninja --install of O2 on ubuntu20.04 gets stuck forever on compilation of new FT0 decoder, which is supposed to be excluded by the guards

The only way to pass through is brute force extra guargs #ifdef NONEXISTING

Could expert suggest better guards?

For the record, this is not only on Ubuntu. The compilation of this translation unit takes ~10min on alibi as well which is CC7. Something needs to be done.

Do we actually have fall-back generic code for this?

To be precise: according to @afurs this is a AMD (FLP) specific code, so on the Intel CPU it should be excluded at all.

Hi, we need this only for Intel CPU and for FLP suite. On other machines it should be excluded

@swenzel yes, unfortunately it takes too much time.

Hi, we need this only for Intel CPU and for FLP suite. On other machines it should be excluded

Ah, ok, sorry, then I misunderstood you, I thought you have special AMD on the FLP.
But even if it takes too long rather than getting stuck, something is fishy: I see that ninja -j20 install eventually runs only this 1 compilation process. In any case, we should exclude it from compilation everywhere except FLP. Perhaps you should agree with @vmcb on some guarding macro enabled in the FLPsuite building only.

Following this up here Cern Authentication
and proposed Annotate FLP builds with special env variable by sawenzel · Pull Request #4229 · alisw/alidist · GitHub + Compile AVX512 decoder only in FLP builds by sawenzel · Pull Request #8956 · AliceO2Group/AliceO2 · GitHub