From owner-freebsd-current@FreeBSD.ORG Sun Jul 30 11:54:31 2006 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 3D99E16A4E1 for ; Sun, 30 Jul 2006 11:54:31 +0000 (UTC) (envelope-from peterjeremy@optushome.com.au) Received: from mail31.syd.optusnet.com.au (mail31.syd.optusnet.com.au [211.29.132.102]) by mx1.FreeBSD.org (Postfix) with ESMTP id 43F8E43D55 for ; Sun, 30 Jul 2006 11:54:30 +0000 (GMT) (envelope-from peterjeremy@optushome.com.au) Received: from turion.vk2pj.dyndns.org (c220-239-19-236.belrs4.nsw.optusnet.com.au [220.239.19.236]) by mail31.syd.optusnet.com.au (8.12.11/8.12.11) with ESMTP id k6UBsScI000800 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO); Sun, 30 Jul 2006 21:54:28 +1000 Received: from turion.vk2pj.dyndns.org (localhost.vk2pj.dyndns.org [127.0.0.1]) by turion.vk2pj.dyndns.org (8.13.6/8.13.6) with ESMTP id k6UBsRaI002633; Sun, 30 Jul 2006 21:54:27 +1000 (EST) (envelope-from peter@turion.vk2pj.dyndns.org) Received: (from peter@localhost) by turion.vk2pj.dyndns.org (8.13.6/8.13.6/Submit) id k6UBsRaJ002632; Sun, 30 Jul 2006 21:54:27 +1000 (EST) (envelope-from peter) Date: Sun, 30 Jul 2006 21:54:27 +1000 From: Peter Jeremy To: Michal Mertl Message-ID: <20060730115427.GD1310@turion.vk2pj.dyndns.org> References: <20060728210154.GC748@turion.vk2pj.dyndns.org> <1154189612.1565.10.camel@genius.i.cz> <20060729205655.GE748@turion.vk2pj.dyndns.org> <20060729211530.GA50342@uk.tiscali.com> <1154212340.3609.18.camel@genius.i.cz> <20060729230214.GI12597@groat.ugcs.caltech.edu> <1154216319.23616.23.camel@genius.i.cz> <1154217036.23616.28.camel@genius.i.cz> <20060730005342.GJ12597@groat.ugcs.caltech.edu> <1154250451.23616.37.camel@genius.i.cz> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="iVCmgExH7+hIHJ1A" Content-Disposition: inline In-Reply-To: <1154250451.23616.37.camel@genius.i.cz> X-PGP-Key: http://members.optusnet.com.au/peterjeremy/pubkey.asc User-Agent: Mutt/1.5.11 Cc: Paul Allen , freebsd-current@freebsd.org Subject: Re: vmstat's entries type X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 30 Jul 2006 11:54:31 -0000 --iVCmgExH7+hIHJ1A Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, 2006-Jul-30 11:07:31 +0200, Michal Mertl wrote: >Paul Allen wrote: >> Which FreeBSD tier-I 64b arch do you have in mind... > >I was referring to what Peter Jeremy said earlier in this thread: > >> RISC architectures usually only have TAS lock primitives (because "inc >> mem" doesn't exist) and so require a spinlock to perform an atomic >> update. This was based on an examination of /usr/src/sys/*/include/atomic.h. It looks like I was overly quick because the RISC architectures are using compare-and-swap, rather than test-and-set primitives - sorry about the error. The details are: - Alpha (RIP) used a loop around a locked conditional store - amd64 appears to support RMW - arm doesn't support 64-bit atomic operations - i386 doesn't support 64-bit atomic operations (but could implement them using cmpxchg8b in a loop) - ia64 uses cmpxchg in a loop - ppc doesn't support 64-bit atomic operations - sparc64 uses cas in a loop. Whilst true spinlocks are not needed, amd64 is the only architecture FreeBSD supports that does not require some sort of loop to perform a 64-bit atomic operation. --=20 Peter Jeremy --iVCmgExH7+hIHJ1A Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.4 (FreeBSD) iD8DBQFEzJ3z/opHv/APuIcRAvVoAJwJlui519oOiZLyP8+5iFYaitQ10wCePe84 eyYj5Yh1vv42M52G46YwlBg= =mU7A -----END PGP SIGNATURE----- --iVCmgExH7+hIHJ1A--