From owner-freebsd-chat Wed Dec 8 17:33:10 1999 Delivered-To: freebsd-chat@freebsd.org Received: from lariat.lariat.org (lariat.lariat.org [206.100.185.2]) by hub.freebsd.org (Postfix) with ESMTP id CA6FF151E9; Wed, 8 Dec 1999 17:32:52 -0800 (PST) (envelope-from brett@lariat.org) Received: from mustang (IDENT:ppp0.lariat.org@lariat.lariat.org [206.100.185.2]) by lariat.lariat.org (8.9.3/8.9.3) with ESMTP id SAA23406; Wed, 8 Dec 1999 18:31:15 -0700 (MST) Message-Id: <4.2.0.58.19991208182954.048a3460@localhost> X-Sender: brett@localhost X-Mailer: QUALCOMM Windows Eudora Pro Version 4.2.0.58 Date: Wed, 08 Dec 1999 18:31:07 -0700 To: Alfred Perlstein From: Brett Glass Subject: Re: Yahoo hacked last night Cc: Roelof Osinga , Jonathon McKitrick , Kris Kennaway , freebsd-chat In-Reply-To: References: <4.2.0.58.19991208172738.0495eef0@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org At 06:19 PM 12/8/1999 , Alfred Perlstein wrote: >> So, Intel had no incentive to make the instructions which manipulated > > segments fast. To this day, Pentiums support them only for downward > > compatibility and to allow the implementation of VMs. The segmentation > > instructions are microcoded rather than hardwired, and can cause > > expensive pipeline stalls or (worse) flushes if you use them. > >So they really can only be done in page sized chunks... :) No, you just have to be willing to take a hit of about 60 cycles per function call, worst case. The thing is, with clock speeds ready to hit 1 MHz, this is getting to be a trivial amount of overhead. --Brett Glass To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message