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[24.6.216.183]) by smtp.gmail.com with ESMTPSA id w8sm5326685pgk.46.2021.02.25.01.32.57 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 25 Feb 2021 01:32:58 -0800 (PST) From: Nadav Amit Message-Id: Content-Type: multipart/signed; boundary="Apple-Mail=_41CB083A-5C98-4549-BEB4-96CA2ADD4E60"; protocol="application/pgp-signature"; micalg=pgp-sha256 Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.60.0.2.21\)) Subject: Re: [RFC 0/6] x86: prefetch_page() vDSO call Date: Thu, 25 Feb 2021 01:32:56 -0800 In-Reply-To: <64538CCF-AD11-43C2-9632-E054301F9E6D@gmail.com> Cc: Linux-MM , LKML , Hugh Dickins , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Sean Christopherson , Andrew Morton , x86@kernel.org To: Peter Zijlstra References: <20210225072910.2811795-1-namit@vmware.com> <64538CCF-AD11-43C2-9632-E054301F9E6D@gmail.com> X-Mailer: Apple Mail (2.3654.60.0.2.21) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Apple-Mail=_41CB083A-5C98-4549-BEB4-96CA2ADD4E60 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > On Feb 25, 2021, at 12:52 AM, Nadav Amit wrote: >=20 >=20 >=20 >> On Feb 25, 2021, at 12:40 AM, Peter Zijlstra = wrote: >>=20 >> On Wed, Feb 24, 2021 at 11:29:04PM -0800, Nadav Amit wrote: >>> From: Nadav Amit >>>=20 >>> Just as applications can use prefetch instructions to overlap >>> computations and memory accesses, applications may want to overlap = the >>> page-faults and compute or overlap the I/O accesses that are = required >>> for page-faults of different pages. [ [ snip ] >> Interesting, but given we've been removing explicit prefetch from = some >> parts of the kernel how useful is this in actual use? I'm thinking = there >> should at least be a real user and performance numbers with this = before >> merging. >=20 > Can you give me a reference to the =E2=80=9Cremoving explicit prefetch = from some > parts of the kernel=E2=80=9D? Oh. I get it - you mean we remove we remove the use of explicit memory prefetch from the kernel code. Well, I don=E2=80=99t think it is really = related, but yes, performance numbers are needed. --Apple-Mail=_41CB083A-5C98-4549-BEB4-96CA2ADD4E60 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEESJL3osl5Ymx/w9I1HaAqSabaD1oFAmA3bsgACgkQHaAqSaba D1qI7A//U0PnZXNVHZqLmdN2PfFUqLYy/Qh8jX882OkqHSofgdFMg+rMZBngRn9H g2iXsmlpxVhWqQC0O7/Z/s2LBM7e2lbemWIhkJWwDK2cyYo1Y/ZkDweil8adXp7u fUIiS4gxSnd3qp7sJN3si9fZW7zd7DinSktSCH1RvmN8exMqW0bnjYuStJlE3sTf Hl/CU1UydIH+XzxWhl7f0SVMxe8RCWYJ7CO+19gDLuP1+TTmVoOeFa6beV5ctaEp dBqTDslBNIZkWXP27Y32ENkb3hQleQF7YSOM+Ust835v/o46bjL6ynBoEE4r6WYa baYRKAM0Tq9RCcHAiPOwcmcwKez0Fi0+p9Y5NJxc6UFYKmoThxks7ADqkiOXxFjv uvfhNSpdI6qC0RclIuSCG2pkpj85kbuSHCrtZ3GBvsVMi26PPipBWWR4bwOSKYfE WapHT75BlsCdIPrRZw3WQ1Gid4nh8wLCue/D26yylzxl7VKReVOv5UQTgySb5vH5 JX4B8FcgqSct19kwe6K3+x2RGrUytIQWQxD7PfM1Ny4xI7aqtikrbMqB3wmF3Zv4 7skYi/4qwnXy+ZuXyka8VHWsG6IeChLi/IMat69Klb0O7eLYfFLLguTyO3eL0mVH zXAuaE39u6HrCIvEp+xKJ+WhEOxHIbeLmTvdvDZtcz4JDO+qeX8= =LWIC -----END PGP SIGNATURE----- --Apple-Mail=_41CB083A-5C98-4549-BEB4-96CA2ADD4E60--