From: Borislav Petkov <bp@alien8.de>
To: Ankur Arora <ankur.a.arora@oracle.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kirill@shutemov.name, mhocko@kernel.org,
boris.ostrovsky@oracle.com, konrad.wilk@oracle.com,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Jiri Slaby <jslaby@suse.cz>,
Herbert Xu <herbert@gondor.apana.org.au>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Subject: Re: [PATCH 4/8] x86/asm: add clear_page_nt()
Date: Wed, 14 Oct 2020 21:56:14 +0200 [thread overview]
Message-ID: <20201014195614.GB18196@zn.tnic> (raw)
In-Reply-To: <20201014083300.19077-5-ankur.a.arora@oracle.com>
On Wed, Oct 14, 2020 at 01:32:55AM -0700, Ankur Arora wrote:
> This can potentially improve page-clearing bandwidth (see below for
> performance numbers for two microarchitectures where it helps and one
> where it doesn't) and can help indirectly by consuming less cache
> resources.
>
> Any performance benefits are expected for extents larger than LLC-sized
> or more -- when we are DRAM-BW constrained rather than cache-BW
> constrained.
"potentially", "expected", I don't like those formulations. Do you have
some actual benchmark data where this shows any improvement and not
microbenchmarks only, to warrant the additional complexity?
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2020-10-14 19:56 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-14 8:32 [PATCH 0/8] Use uncached writes while clearing gigantic pages Ankur Arora
2020-10-14 8:32 ` [PATCH 1/8] x86/cpuid: add X86_FEATURE_NT_GOOD Ankur Arora
2020-10-14 8:32 ` [PATCH 2/8] x86/asm: add memset_movnti() Ankur Arora
2020-10-14 8:32 ` [PATCH 3/8] perf bench: " Ankur Arora
2020-10-14 8:32 ` [PATCH 4/8] x86/asm: add clear_page_nt() Ankur Arora
2020-10-14 19:56 ` Borislav Petkov [this message]
2020-10-14 21:11 ` Ankur Arora
2020-10-14 8:32 ` [PATCH 5/8] x86/clear_page: add clear_page_uncached() Ankur Arora
2020-10-14 11:10 ` kernel test robot
2020-10-14 13:04 ` kernel test robot
2020-10-14 15:45 ` Andy Lutomirski
2020-10-14 19:58 ` Borislav Petkov
2020-10-14 21:07 ` Andy Lutomirski
2020-10-14 21:12 ` Borislav Petkov
2020-10-15 3:37 ` Ankur Arora
2020-10-15 10:35 ` Borislav Petkov
2020-10-15 21:20 ` Ankur Arora
2020-10-16 18:21 ` Borislav Petkov
2020-10-15 3:21 ` Ankur Arora
2020-10-15 10:40 ` Borislav Petkov
2020-10-15 21:40 ` Ankur Arora
2020-10-14 20:54 ` Ankur Arora
2020-10-14 8:32 ` [PATCH 6/8] mm, clear_huge_page: use clear_page_uncached() for gigantic pages Ankur Arora
2020-10-14 15:28 ` Ingo Molnar
2020-10-14 19:15 ` Ankur Arora
2020-10-14 8:32 ` [PATCH 7/8] x86/cpu/intel: enable X86_FEATURE_NT_GOOD on Intel Broadwellx Ankur Arora
2020-10-14 15:31 ` Ingo Molnar
2020-10-14 19:23 ` Ankur Arora
2020-10-14 8:32 ` [PATCH 8/8] x86/cpu/amd: enable X86_FEATURE_NT_GOOD on AMD Zen Ankur Arora
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