From owner-freebsd-smp Sat Dec 14 15:08:48 1996 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.4/8.8.4) id PAA26319 for smp-outgoing; Sat, 14 Dec 1996 15:08:48 -0800 (PST) Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.211]) by freefall.freebsd.org (8.8.4/8.8.4) with SMTP id PAA26289; Sat, 14 Dec 1996 15:08:41 -0800 (PST) Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id PAA22458; Sat, 14 Dec 1996 15:45:28 -0700 From: Terry Lambert Message-Id: <199612142245.PAA22458@phaeton.artisoft.com> Subject: Re: some questions concerning TLB shootdowns in FreeBSD To: toor@dyson.iquest.net (John S. Dyson) Date: Sat, 14 Dec 1996 15:45:28 -0700 (MST) Cc: phk@critter.tfs.com, dyson@freebsd.org, peter@spinner.dialix.com, smp@freebsd.org, haertel@ichips.intel.com In-Reply-To: <199612142222.RAA05499@dyson.iquest.net> from "John S. Dyson" at Dec 14, 96 05:22:22 pm X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-smp@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > > Is there any cheap way to keep a refcount (or bitmap) per vm-object so > > we can see if we need to kick the other CPUs if we fiddle it ? > > That would be tricky if we can freely reschedule processes on other > cpu's... It would entail traversing the map for the process when > the process is scheduled. Normally, there is also no notification > when a page table entry is fetched into the TLB. Such notification > can be arranged on the advanced X86 processors, but it doesn't > appear to be a guaranteed type thing. You could simplify this a lot by preferential scheduling. You could also keep a bitmap of the virtual address space and examine only those areas where a bitmap collides... Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.