From owner-freebsd-hackers Thu May 21 05:23:56 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id FAA27507 for freebsd-hackers-outgoing; Thu, 21 May 1998 05:23:56 -0700 (PDT) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from sumatra.americantv.com (sumatra.americantv.com [207.170.17.37]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id FAA27501 for ; Thu, 21 May 1998 05:23:52 -0700 (PDT) (envelope-from jlemon@americantv.com) Received: from right.PCS (right.PCS [148.105.10.31]) by sumatra.americantv.com (8.8.5/8.8.5) with ESMTP id HAA10060; Thu, 21 May 1998 07:23:34 -0500 (CDT) Received: (from jlemon@localhost) by right.PCS (8.6.13/8.6.4) id HAA00066; Thu, 21 May 1998 07:23:03 -0500 Message-ID: <19980521072302.21950@right.PCS> Date: Thu, 21 May 1998 07:23:02 -0500 From: Jonathan Lemon To: Chuck Robey Cc: Soren Kristensen , hackers@FreeBSD.ORG Subject: Re: Original PC and talk References: <3563A210.31CF@alameda.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.61.1 In-Reply-To: ; from Chuck Robey on May 05, 1998 at 11:47:17PM -0400 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On May 05, 1998 at 11:47:17PM -0400, Chuck Robey wrote: > All those tricks (the same ones) are why processors like the DEC Alpha > are so hot. Things like register renaming don't give you much > improvement if you're talking about such a tiny humber of registers to > begin with (referring to the X86 here). Huh? Register renaming (from the architecture's point of view) only refers to the internal on-chip registers (reservation stations), not the externally visible registers (from the compiler's point of view). There can be a lot of internal registers. These are marshalled and committed (or squashed) by the reorder buffer at the end of execution (assuming a relatively modern chip here). This reordering does give a performance boost, even if there are only a few architecturally visible registers, as in the case of x86. -- Jonathan To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message