14/07/2020 16:38, Stephen Hemminger: > "Kinsella, Ray" <m...@ashroe.eu> wrote: > > On 13/07/2020 23:19, Stephen Hemminger wrote: > > > Did anyone else see the recent AVX512 discussion from Linus: > > > "I hope AVX512 dies a painful death, and that Intel starts fixing real > > > problems > > > instead of trying to create magic instructions to then create > > > benchmarks that they can look good on. > > > > Yup - I saw this one. > > Sweeping statements like these are good to provoke debate, the truth is > > generally more nuanced. > > If you continue to read the post, Linus appears to be mostly questioning > > microprocessor design decisions. > > > > That is an interesting discussion, however the reality is that the > > technology does exists and may be beneficial for Packet Processing. > > > > I would suggest, we continue to apply the same logic governing adoption of > > any technology by DPDK. > > When the technology is present and a clear benefit is shown, we use it with > > caution. > > > > In the case of Vladimir's patch, > > the user has to explicitly switch on the AVX512 lookup with > > RTE_FIB_DIR24_8_VECTOR_AVX512. > > Using what is available makes sense in DPDK.
Why does it require explicit enabling in application? AVX512 is not reliable enough to be automatically used when available?
