From owner-freebsd-arch@FreeBSD.ORG Mon Aug 18 20:26:31 2014 Return-Path: Delivered-To: arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 217179AF for ; Mon, 18 Aug 2014 20:26:31 +0000 (UTC) Received: from mail-pd0-f170.google.com (mail-pd0-f170.google.com [209.85.192.170]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id DEEA533B7 for ; Mon, 18 Aug 2014 20:26:30 +0000 (UTC) Received: by mail-pd0-f170.google.com with SMTP id g10so8306491pdj.1 for ; Mon, 18 Aug 2014 13:26:24 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:sender:content-type:mime-version:subject:from :in-reply-to:date:cc:message-id:references:to; bh=qUaQfSoyxwXZHjgbkO8snPN3xfU+oyxS+aaJGM92k80=; b=i6cfsNql7eahq12qhbfzM3sYY6jeBUUscyn3McEbGMYvUERc0Dc2fsRCHEsIRfbfMM 1FLtN2O3C1mDB1TiwzEH4dnL8vrkaZ4i8LEdfNSyRmkEot/P68v2iIL3Rp86jSRiT2g6 YlXPbRX5W2wAcvSubFq58zq3+hKDXpnCHcWd1dLPFTS+5OSZvOzB17H90gP8gWAMcbbw kdR7Wf9xAd07QCDJHwcZkxo9Ld+GT4qjfRp6x9H7y7exxiXWX5y5i7nki2R3C2fa8D9m 1fgWaUuv/LSMFbPht7r2twkUZntFLZ20WCjTKxGTnFr+nRY3lT+g4hN4AVBZ3c5pR1oQ yEqA== X-Gm-Message-State: ALoCoQnTZBly1//yBroe/1oKFc8j1kDiL4TG1c+V6eDM+ItyiegfPO5c4M0+dXedoLD7gVrsbLrK X-Received: by 10.70.44.70 with SMTP id c6mr36094617pdm.75.1408393584700; Mon, 18 Aug 2014 13:26:24 -0700 (PDT) Received: from lgmac-jku.corp.netflix.com (dc1-prod.netflix.com. [69.53.236.251]) by mx.google.com with ESMTPSA id hk7sm26086705pdb.4.2014.08.18.13.26.23 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 18 Aug 2014 13:26:23 -0700 (PDT) Sender: Warner Losh Content-Type: multipart/signed; boundary="Apple-Mail=_4C658C27-60E7-4EE6-BC54-329709FB8759"; protocol="application/pgp-signature"; micalg=pgp-sha512 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Subject: Re: superpages for UMA From: Warner Losh In-Reply-To: <53F25E60.5050109@freebsd.org> Date: Mon, 18 Aug 2014 14:26:21 -0600 Message-Id: <257A0976-7C5E-4029-AF32-BFB3A6C60832@bsdimp.com> References: <53F215A9.8010708@FreeBSD.org> <20140818183925.GP2737@kib.kiev.ua> <53F25E60.5050109@freebsd.org> To: Peter Grehan X-Mailer: Apple Mail (2.1878.6) Cc: arch@freebsd.org X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 18 Aug 2014 20:26:31 -0000 --Apple-Mail=_4C658C27-60E7-4EE6-BC54-329709FB8759 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 On Aug 18, 2014, at 2:13 PM, Peter Grehan wrote: >> Newer Intel CPUs have more entries, and AMD CPUs have long (since >> Barcelona) had more. In particular, they allow 2 MB page mappings to = be >> cached in a larger L2 TLB. Nowadays, the trouble is with the 1 GB = pages. >> A lot of CPUs still only support an 8 entry, 1 level TLB for 1 GB = pages. >=20 > There are new(ish) ones effectively without 1GB pages. =46rom the = "Software Optimization Guide for AMD Family 16h Processors" >=20 > "Smashing" > ... > "when the Family 16h processor encounters a 1-Gbyte page size, it will = smash translations of that 1-Gbyte region into 2-Mbyte TLB entries, each > of which translates a 2-Mbyte region of the 1-Gbyte page." =93we=92ll emulate this feature designed to make things go faster in = hardware in software by doing the very thing that makes it go slow in = hardware.=94 Fun times. Performance Smashing! Warner --Apple-Mail=_4C658C27-60E7-4EE6-BC54-329709FB8759 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJT8mFtAAoJEGwc0Sh9sBEAILYQAJvi/5avR/rBR2VivBhiWVIG 3HjtyIPbTu2XE9OiyF+h4BkREZ9Wu1dyUgKnCKqYM4DPkTGdSAcRGCdSa8GqDYva xV0QU2JH2DpjXZgmlO5JKYVzDmn/7GJVd5Ix71jg5yneg8kKl4U14ZxXcboLAY36 8t020p6vzIKNkz352kXYqLR/aCle3opbzmXTtq3lMqZHc3UMptq+XIG8m91SlQWc 24CSuJOV1W1rvi0RJ2iFR3KYE9cxvA7iUTd8RsqV5aevc22DZsjBLYRuwaA5Z2uy xFVflbrv3bA2vxw1GdtJ/W3LiD1oH+GP0jTGHMMG/jmJTlL6JbnhHR3MT0l3Ue57 dsrI24GV0aarjjHx282cyn77RTsrR0N6Kn0mw1usRWYixY/k5JNqbdQoIXB2Fqyx Mt4Axj3jm9kIjRCJNVx5XCix7md2SU402ac8zXdreD42IvyyXfc6cgWXvd8WNXXK XdEyvRbQs50ktb5eXBpm9yqsRcOl6d0C0tyP7SaDCevmTn6+405Z6QytK3L9Pc+Y yWC5hFaBLw/26JFhjF2E7ysfnfH3Nn+jIS5CgmuPzzp+qXYfmRmf5HQyJ01fr0lh b+tSS4sJV1WOC+tEt/2Joiw3llJYiSO07x4hT/GatVZtk1e4RlRER/AX0suVyF4F Ry22w2qx+U8yfO094Ef1 =h2+C -----END PGP SIGNATURE----- --Apple-Mail=_4C658C27-60E7-4EE6-BC54-329709FB8759--