amoeba commented on code in PR #40374: URL: https://github.com/apache/arrow/pull/40374#discussion_r1515601896
########## docs/source/cpp/env_vars.rst: ########## @@ -132,11 +132,15 @@ that changing their value later will have an effect. .. envvar:: ARROW_USER_SIMD_LEVEL - The SIMD optimization level to select. By default, Arrow C++ detects - the capabilities of the current CPU at runtime and chooses the best - execution paths based on that information. One can override the detection - by setting this environment variable to a well-defined value. - Supported values are: + The maximum SIMD optimization level selectable at runtime. Useful for + comparing the performance impact of enabling or disabling respective code + paths or working around situations where instructions are supported but are + either buggy or not performant. Review Comment: Thanks for taking a look. There may be a better word here...By buggy I was referring to the comment in https://github.com/apache/arrow/issues/40333#issuecomment-1977142577 mentioning situations where like running under a hypervisor where cpu detection reports that an instruction is supported but it's not handled correctly by the hypervisor. I'm not familiar with this so I don't know what "not handled correctly" really means. Maybe instead of buggy, say "where instructions are supported but are not performant or cause other issues"? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
