[ARROW-11905] [C++] SIMD info always returning none on MacOS

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0.0
• Component/s: C++
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/27746
• Assignee: Antoine Pitrou
• Reporter: Jonathan Keane
• Created: 08/Mar/21 14:33
• Updated: 11/Jan/23 08:22
• Resolved: 09/Mar/21 13:45

Description

I'm helping with ARROW-11507 and in testing it I noticed something odd, I'm getting none and none for both simd_level and detected_simd_level which seems odd. I also tried it in pyarrow (below) and I'm getting the same thing (this was built off of HEAD of apache/arrow) so I suspect that this is something lower than either of them (and in both runtime_info is a think wrapper around the c++).

>>> import pyarrow as pa
>>> pa.runtime_info()
RuntimeInfo(simd_level='none', detected_simd_level='none')

I do see the following when building:

--   ARROW_SIMD_LEVEL=SSE4_2 [default=NONE|SSE4_2|AVX2|AVX512]
--       Compile-time SIMD optimization level
--   ARROW_RUNTIME_SIMD_LEVEL=MAX [default=NONE|SSE4_2|AVX2|AVX512|MAX]
--       Max runtime SIMD optimization level
and sse/avx etc are built:

-- Performing Test CXX_SUPPORTS_SSE4_2
-- Performing Test CXX_SUPPORTS_SSE4_2 - Success
-- Performing Test CXX_SUPPORTS_AVX2
-- Performing Test CXX_SUPPORTS_AVX2 - Success
-- Performing Test CXX_SUPPORTS_AVX512
-- Performing Test CXX_SUPPORTS_AVX512 - Success

I've also tried confirming that ARROW_USER_SIMD_LEVEL is unset, and tried setting it explicitly:

(pyarrow-source) jkeane@het python % ARROW_USER_SIMD_LEVEL=sse4_2 python
Python 3.9.2 (default, Feb 24 2021, 13:26:09)
[Clang 12.0.0 (clang-1200.0.32.29)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import pyarrow as pa
>>> pa.runtime_info()
RuntimeInfo(simd_level='none', detected_simd_level='none')

I've tested it on two macOS machines (both running on intel chips) and both had the same behavior above. This appears to work on linux machines just fine.

Issue Links

• links to: GitHub Pull Request #9657