This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: V5 [PATCH 1/2] x86: Add <sys/platform/x86.h>
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Florian Weimer <fweimer at redhat dot com>
- Cc: libc-alpha at sourceware dot org
- Date: Wed, 24 Oct 2018 02:29:42 -0700
- Subject: Re: V5 [PATCH 1/2] x86: Add <sys/platform/x86.h>
- References: <20180927194327.7683-1-hjl.tools@gmail.com> <20180927194327.7683-2-hjl.tools@gmail.com> <874ldb9036.fsf@oldenburg.str.redhat.com>
On 10/24/18, Florian Weimer <fweimer@redhat.com> wrote:
> * H. J. Lu:
>
>> +@defmac HAS_CPU_FEATURE(name)
>> +
>> +Evaluate to true if the CPU feature @code{name} is supported as
>> indicated
>> +by @code{CPUID} instruction. The available features are:
>
> I'm still puzzled why we expose this function. It will only confuse
> programmers.
A use case: AVX512 bits can be used to tell Xeon Phi from Skylake
sever even if AVX512 instructions aren't used/needed at all.
>> +@defmac CPU_FEATURE_USABLE(name)
>> +
>> +Evaluate to true if the architecture feature @code{name} is usable.
>> +The supported features are:
>
> This is the only interface which should be exposed.
>
> Thanks,
> Florian
>
--
H.J.