From: Thiago Macieira <thiago.macieira@intel.com>
To: Florian Weimer <fweimer@redhat.com>, "H.J. Lu" <hjl.tools@gmail.com>
Cc: "H.J. Lu via Libc-alpha" <libc-alpha@sourceware.org>,
Arjan van de Ven <arjan@linux.intel.com>,
liuhongt <hongtao.liu@intel.com>,
Hongyu Wang <hongyu.wang@intel.com>
Subject: Re: [PATCH] x86: Don't set Prefer_No_AVX512 for processors with AVX512 and AVX-VNNI
Date: Tue, 07 Dec 2021 08:22:52 -0800 [thread overview]
Message-ID: <52871468.kDZyW8NQCg@tjmaciei-mobl5> (raw)
In-Reply-To: <CAMe9rOoZVBuTaT9XmmBZs-KUFFrNOw3R0_nroUH7n9JJe_J5nQ@mail.gmail.com>
On Tuesday, 7 December 2021 07:52:44 PST H.J. Lu wrote:
> > Would it make sense to run more extensive tests, or should we wait for
> > someone with production silicon to show up?
>
> GCC is a heavy user of memcpy/memset, which is a good proxy of
> ZMM load/store impact on CPU frequency. We need to run the same
> test on a production Rocket Lake.
Can someone run the same test on an Ice Lake? That will also answer whether we
should enable the same thing for ICL / ICX.
RKL is a Cypress Cove, so I'd expect it to have the same performance numbers
as ICL's Sunny Cove. The data I have says that, in theory, we should not see a
frequency drop for 512-bit memcpy / memset on ICL or TGL, but I haven't got
experimental data confirming that. And I can't really run the benchmark test
on a laptop with very poor thermal dissipation (freq drops to 1500 MHz all on
its own).
If a good ICL has the drop, then I'd assume RKL will too.
--
Thiago Macieira - thiago.macieira (AT) intel.com
Software Architect - Intel DPG Cloud Engineering
next prev parent reply other threads:[~2021-12-07 16:27 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-06 3:23 H.J. Lu
2021-12-07 7:47 ` Noah Goldstein
2021-12-07 12:53 ` H.J. Lu
2021-12-07 13:17 ` Arjan van de Ven
2021-12-07 13:34 ` H.J. Lu
2021-12-07 14:05 ` Florian Weimer
2021-12-07 14:15 ` H.J. Lu
2021-12-07 15:47 ` Florian Weimer
2021-12-07 15:52 ` H.J. Lu
2021-12-07 16:22 ` Thiago Macieira [this message]
2021-12-07 19:32 ` Noah Goldstein
2022-04-23 1:51 ` Sunil Pandey
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