From: "H.J. Lu" <hjl.tools@gmail.com>
To: Florian Weimer <fw@deneb.enyo.de>
Cc: Andy Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"Bae, Chang Seok" <chang.seok.bae@intel.com>,
"Carlos O'Donell" <carlos@redhat.com>,
Rich Felker <dalias@libc.org>,
libc-alpha <libc-alpha@sourceware.org>
Subject: Re: Why does glibc use AVX-512?
Date: Fri, 26 Mar 2021 13:43:51 -0700 [thread overview]
Message-ID: <CAMe9rOp9S0A++Gf1hRoAL4tENk-xRk3yc=_Vx=V_+K63DOXspA@mail.gmail.com> (raw)
In-Reply-To: <877dltd569.fsf@mid.deneb.enyo.de>
On Fri, Mar 26, 2021 at 1:35 PM Florian Weimer <fw@deneb.enyo.de> wrote:
>
> All this needs to work transparently without user intervention. We
> cannot require firmware upgrades to fix the incorrect RTM reporting
> issue (the bug I referenced). I think we can require software updates
> which tell glibc when to use RTM-enabled string functions if the
> dynamic selection does not work (either for performance reasons, or
> because of the RTM reporting bug).
>
> I want to avoid a situation where one in eight processes fail to work
> correctly because the CPUID checks ran on CPU 0, where RTM is reported
> as available, and then we trap when executing XTEST on other CPUs.
glibc can disable RTM based on CPU model and stepping.
--
H.J.
next prev parent reply other threads:[~2021-03-26 20:44 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-26 4:38 Andy Lutomirski
2021-03-26 10:06 ` Borislav Petkov
2021-03-26 18:17 ` Andy Lutomirski
2021-03-26 12:12 ` Florian Weimer
2021-03-26 18:14 ` Andy Lutomirski
2021-03-26 19:34 ` Florian Weimer
2021-03-26 19:47 ` Andy Lutomirski
2021-03-26 20:06 ` Andrew Cooper
2021-03-26 20:35 ` Florian Weimer
2021-03-26 20:43 ` H.J. Lu [this message]
2021-03-26 20:48 ` Andy Lutomirski
2021-03-26 21:11 ` Florian Weimer
2021-03-26 21:21 ` Andy Lutomirski
2021-03-26 13:32 ` David Laight
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