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Re: [PATCH] x86: Set Prefer_No_VZEROUPPER if AVX512ER is available
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Florian Weimer <fweimer at redhat dot com>
- Cc: GNU C Library <libc-alpha at sourceware dot org>
- Date: Mon, 17 Apr 2017 13:13:53 -0700
- Subject: Re: [PATCH] x86: Set Prefer_No_VZEROUPPER if AVX512ER is available
- Authentication-results: sourceware.org; auth=none
- References: <20170417195412.GA8487@intel.com> <4f793a5a-d60f-67e8-a100-c1ae2dc8beb2@redhat.com>
On Mon, Apr 17, 2017 at 1:06 PM, Florian Weimer <fweimer@redhat.com> wrote:
> On 04/17/2017 09:54 PM, H.J. Lu wrote:
>>
>> Since AVX512ER is unique to Xeon Phi, set Prefer_No_VZEROUPPER if
>> AVX512ER is available.
>
>
> This approach doesn't seem very future-proof to me.
>
AVX512ER won't be implemented in any Xeon processors and it will be in
all Xeon Phi processors. In this way, we don't need to check CPU model
numbers when setting Prefer_No_VZEROUPPER. It will work with current
and future Xeon Phi and non-Xeon Phi processors.
--
H.J.