Date: Wed, 17 Jan 2007 20:41:44 +0100 From: Ivan Voras <ivoras@fer.hr> To: Bruce Evans <bde@zeta.org.au> Cc: freebsd-current@freebsd.org, freebsd-arch@freebsd.org Subject: Optimized copy&move (was: Re: [PATCH] Mantaining turnstile aligned to 128 bytes in i386 CPUs) Message-ID: <45AE7BF8.10703@fer.hr> In-Reply-To: <20070117224812.Q23194@besplex.bde.org> References: <3bbf2fe10607250813w8ff9e34pc505bf290e71758@mail.gmail.com> <3bbf2fe10607251004wf94e238xb5ea7a31c973817f@mail.gmail.com> <3bbf2fe10607261127p3f01a6c3w80027754f7d4e594@mail.gmail.com> <3bbf2fe10607281004o6727e976h19ee7e054876f914@mail.gmail.com> <3bbf2fe10701160851r79b04464m2cbdbb7f644b22b6@mail.gmail.com> <20070116154258.568e1aaf@pleiades.nextvenue.com> <b1fa29170701161355lc021b90o35fa5f9acb5749d@mail.gmail.com> <eoji7s$cit$2@sea.gmane.org> <b1fa29170701161425n7bcfe1e5m1b8c671caf3758db@mail.gmail.com> <eojlnb$qje$1@sea.gmane.org> <b1fa29170701161534n1f6c3803tbb8ca60996d200d9@mail.gmail.com> <eojok9$449$1@sea.gmane.org> <20070117134022.V18339@besplex.bde.org> <20070117224812.Q23194@besplex.bde.org>
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This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig238686BF5CDEB8B50F4252DA Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Bruce Evans wrote: > And MMX/XMM registers ar not needed to get movnt on machines with SSE2,= > since movnti is part of SSE2. This reduces the advantages of using MMX= /XMM > registers on P4's and A64's in 32-bit mode to the non-nt parts of the > above (fully cached case), which I think are less important than the nt= > parts. Hmm, I'm looking at i386/i386/support.s and there are several versions of bcopy and bmove functions, including some that optimize by using FPU registers (large_i586_bcopy_loop), and a version that uses movnti (sse2_pagezero), but I can't find the bit of magic which glues them to bzero() call. Also, as as I can tell by the comments, the FPU version works by manually saving context... why is this possible (i.e. won't something preempt it?) --------------enig238686BF5CDEB8B50F4252DA Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.4 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFFrnv5ldnAQVacBcgRAiR4AKCDQ6LnV8f1easSMto1WjFvD74GPgCfdciE 08MOyCrxIQhroC5tgvhqJo0= =7h/R -----END PGP SIGNATURE----- --------------enig238686BF5CDEB8B50F4252DA--
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