From owner-freebsd-smp  Tue Feb  4 17:27:22 1997
Return-Path: <owner-smp>
Received: (from root@localhost)
          by freefall.freebsd.org (8.8.5/8.8.5) id RAA07731
          for smp-outgoing; Tue, 4 Feb 1997 17:27:22 -0800 (PST)
Received: from caipfs.rutgers.edu (root@caipfs.rutgers.edu [128.6.155.100])
          by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id RAA07722
          for <freebsd-smp@freebsd.org>; Tue, 4 Feb 1997 17:27:19 -0800 (PST)
Received: from jenolan.caipgeneral (jenolan.rutgers.edu [128.6.111.5]) by caipfs.rutgers.edu (8.7.6/8.7.3) with SMTP id UAA05067; Tue, 4 Feb 1997 20:24:28 -0500 (EST)
Received: by jenolan.caipgeneral (SMI-8.6/SMI-SVR4)
	id UAA03391; Tue, 4 Feb 1997 20:24:12 -0500
Date: Tue, 4 Feb 1997 20:24:12 -0500
Message-Id: <199702050124.UAA03391@jenolan.caipgeneral>
From: "David S. Miller" <davem@jenolan.rutgers.edu>
To: nate@mt.sri.com
CC: julian@whistle.com, toor@dyson.iquest.net, michaelh@cet.co.jp,
        freebsd-smp@freebsd.org
In-reply-to: <199702050105.SAA09082@rocky.mt.sri.com> (message from Nate
	Williams on Tue, 4 Feb 1997 18:05:24 -0700 (MST))
Subject: Re: [?] TLB Flushing on Context Switch PPro vs. Pentium
Sender: owner-smp@freebsd.org
X-Loop: FreeBSD.org
Precedence: bulk

   Date: Tue, 4 Feb 1997 18:05:24 -0700 (MST)
   From: Nate Williams <nate@mt.sri.com>

   > I believe linux now does this.

   I know Linus toyed with this, but ended up going back due to bugs
   in many Pentium chips.  (My Pentium will not work with 4MB pages,
   and it's a P100 w/out the FDIV bug.)

Ifdef'd out by default in 2.0.x, if enabled in that code it can then
be dynamically disabled via the mem=nopentium boot time command line
option.

In 2.1.x it is completely enabled.