From: Florian Weimer <fweimer@redhat.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: libc-alpha@sourceware.org, linux-api@vger.kernel.org,
x86@kernel.org, linux-arch@vger.kernel.org,
"H.J. Lu" <hjl.tools@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: x86 CPU features detection for applications (and AMX)
Date: Thu, 08 Jul 2021 16:41:09 +0200 [thread overview]
Message-ID: <87lf6gswai.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <ba004c50-a630-27f4-5fb0-c6ad2b1f1e06@intel.com> (Dave Hansen's message of "Thu, 8 Jul 2021 07:36:44 -0700")
* Dave Hansen:
> That's kinda my whole point.
>
> These *MUST* be curated to be meaningful. Right now, someone just
> dumped a set of CPUID bits into the documentation.
>
> The interface really needs *three* modes:
>
> 1. Yes, the CPU/OS supports this feature
> 2. No, the CPU/OS doesn't support this feature
> 3. Hell if I know, never heard of this feature
>
> The interface really conflates 2 and 3. To me, that makes it
> fundamentally flawed.
That's an interesing point.
3 looks potentially more useful than the feature/usable distinction to
me.
The recent RTM change suggests that there are more states, but we
probably can't do much about such soft-disable changes.
Thanks,
Florian
next prev parent reply other threads:[~2021-07-08 14:41 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-23 15:04 x86 CPU features detection for applications (and AMX) Florian Weimer
2021-06-23 15:32 ` Dave Hansen
2021-07-08 6:05 ` Florian Weimer
2021-07-08 14:19 ` Dave Hansen
2021-07-08 14:31 ` Florian Weimer
2021-07-08 14:36 ` Dave Hansen
2021-07-08 14:41 ` Florian Weimer [this message]
2021-06-25 23:31 ` Thiago Macieira
2021-06-28 12:40 ` Enrico Weigelt, metux IT consult
2021-06-28 13:20 ` Peter Zijlstra
2021-06-30 12:50 ` Enrico Weigelt, metux IT consult
2021-06-30 15:36 ` Thiago Macieira
2021-07-01 7:35 ` Enrico Weigelt, metux IT consult
2021-06-28 15:08 ` Thiago Macieira
2021-06-28 15:27 ` Peter Zijlstra
2021-06-28 16:13 ` Thiago Macieira
2021-06-28 17:11 ` Peter Zijlstra
2021-06-28 17:23 ` Thiago Macieira
2021-06-28 19:08 ` Peter Zijlstra
2021-06-28 19:26 ` Thiago Macieira
2021-06-28 17:43 ` Peter Zijlstra
2021-06-28 19:05 ` Thiago Macieira
2021-06-30 14:32 ` Enrico Weigelt, metux IT consult
2021-06-30 14:34 ` Florian Weimer
2021-06-30 15:16 ` Enrico Weigelt, metux IT consult
2021-06-30 15:38 ` Florian Weimer
2021-07-01 8:08 ` Enrico Weigelt, metux IT consult
2021-07-01 8:21 ` Florian Weimer
2021-07-01 11:59 ` Enrico Weigelt, metux IT consult
2021-07-06 12:57 ` Florian Weimer
2021-06-30 15:29 ` Thiago Macieira
2021-07-01 11:57 ` Enrico Weigelt, metux IT consult
2021-07-08 7:08 ` Florian Weimer
2021-07-08 15:13 ` Thiago Macieira
2021-07-08 17:56 ` Mark Brown
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