There is an std::simd being envisioned. https://en.cppreference.com/w/cpp/experimental/simd/simd
The problem is that we need an implementation that's C++11- or C++14-compliant, that works on major compilers, and that provides accelerations for common instruction sets. It doesn't seem to be the case currently. https://github.com/VcDevel/std-simd Regards Antoine. Le 12/02/2021 à 05:18, Micah Kornfield a écrit : > I'm open to x-simd if others think it is the best option. I think the last > time this came up I expressed this opinion, but if possible it would be > nice to use something that is on its way to become a standard to avoid > abandonment issues but I don't know enough about the space to understand if > this is a real concern. > > On Tue, Feb 9, 2021 at 7:00 PM Yuqi Gu <yuqi...@linaro.org> wrote: > >> Thanks for comments on the SIMD related PR: >> https://github.com/apache/arrow/pull/9424. >> Agree to adopt the *xsimd *as the SIMD wrapper library for Arrow to avoid a >> large maintenance burden. It makes sense. >> >> It seems *ximd *is designed for mathematics calculating and it lacks the >> functions like bit/byte shuffling, byte stream split encoding, ARM SVE >> supporting, etc. >> I'm absolutely willing to contribute the missing functions to *xsimd*. >> >> BRs, >> Yuqi >> >> On Tue, 9 Feb 2021 at 22:08, Antoine Pitrou <anto...@python.org> wrote: >> >>> >>> Le 09/02/2021 à 10:36, Antoine Pitrou a écrit : >>>> >>>> Note that we need to decouple the SIMD level available at compile-time >>>> from the SIMD level available at runtime. That is, we typically build >>>> optional AVX512 accelerations at compile-time, but only enable them at >>>> runtime if the CPU supports AVX512 (and if the environment variable >>>> ARROW_USER_SIMD_LEVEL wasn't forced to a lower value). >>>> >>>> From a quick glance, it's not obvious that xsimd supports that level of >>>> control. Though it may just be undocumented. I will check with the >>>> authors, since I happen to know them. >>> >>> Ok, there shouldn't be any problem on that front. We just need to >>> compile with the right compiler flags to select the desired SIMD level, >>> like we already do currently when compiling multiple versions of a >>> function. >>> >>> I'll note that xsimd isn't very complete. For example, it seems to lack >>> the functions required for byte stream split encoding and decoding. >>> Those functions are exported by libsimdpp under the names "zip_lo" and >>> "zip_hi". >>> >>> libsimdpp, on the other hand, seems to lack maintenance. It hasn't had >>> a commit in one year, and issues and PRs seem to be unanswered. So >>> perhaps xsimd is a better course, provided we want to contribute the >>> missing functions. >>> >>> Regards >>> >>> Antoine. >>> >> >
