Hash :
16deb62f
Author :
Date :
2025-09-12T16:55:45
cpu-supports: a module to honor GLIBC_TUNABLES=glibc.cpu.hwcaps This functionality is useful to allow better test coverage at least, and may be useful for users to tune their environment, avoiding CPU throttling for example. * lib/cpu-supports.h (cpu_supports): A new wrapper that checks that the GLIBC_TUNABLES environment variable allows the hardware feature, before checking with __builtin_cpu_supports(). (cpu_may_support): Only perform the GLIBC_TUNABLES check, which is useful if using other interfaces like getauxval(). (gcc_feature_to_glibc_hwcap): An internal helper that will resolve at compile time with standard optimizations enabled. * lib/cpu-supports.c (hwcap_allowed): Query the GLIBC_TUNABLES environment variable (read once per process), to see if the passed GLIBC_HWCAP is allowed. * modules/cpu-supports: New module definition. * modules/cpu-supports-tests: New test module definition. * tests/test-cpu-supports.c: New tests.