From owner-freebsd-current Thu Mar 30 11:25:42 2000 Delivered-To: freebsd-current@freebsd.org Received: from freesbee.wheel.dk (freesbee.wheel.dk [193.162.159.97]) by hub.freebsd.org (Postfix) with ESMTP id 4076B37BF12; Thu, 30 Mar 2000 11:25:37 -0800 (PST) (envelope-from jesper@skriver.dk) Received: by freesbee.wheel.dk (Postfix, from userid 1001) id E4D563E24; Thu, 30 Mar 2000 21:25:35 +0200 (CEST) Date: Thu, 30 Mar 2000 21:25:35 +0200 From: Jesper Skriver To: Mike Smith Cc: freebsd-current@freebsd.org Subject: Re: SMP buildworld times / performance tests Message-ID: <20000330212535.A49637@skriver.dk> References: <1274.954416252@critter.freebsd.dk> <200003301805.KAA00452@mass.cdrom.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0.1i In-Reply-To: <200003301805.KAA00452@mass.cdrom.com>; from msmith@freebsd.org on Thu, Mar 30, 2000 at 10:05:26AM -0800 Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Thu, Mar 30, 2000 at 10:05:26AM -0800, Mike Smith wrote: > > >> Just following on from this, one thing that I can see immediately being > > >> very important to me at least is a spinlock in the timecounter structure. > > >> Calcru and various other things call microtime(), and we're going to want > > >> to lock out updates and parallel accesses to the timecounter. What > > >> should we be using for an interrupt-disabling spinlock? > > > > > >Nothing. Accesses to the timecounter struct are already MP safe and fast. > > >Only the i8254 timecounter hardware currently needs interrupt-disabling, > > >but it is hopefully never used on SMP machines. > > > > Worse. It is used by default on SMP machines which don't sport the > > PIIX timecounter. > > ie. anything using the PIIX3 or older (think 440FX dual P6 systems, etc.) On the box below, a relative new dual PIII box, with a Intel motherboard, does it use the i8254 or the PIIX timecounter ? Copyright (c) 1992-2000 The FreeBSD Project. Copyright (c) 1982, 1986, 1989, 1991, 1993 The Regents of the University of California. All rights reserved. FreeBSD 4.0-STABLE #0: Mon Mar 27 17:02:42 CEST 2000 root@:/usr/src/sys/compile/REMIE Timecounter "i8254" frequency 1193182 Hz CPU: Pentium III/Pentium III Xeon (496.66-MHz 686-class CPU) Origin = "GenuineIntel" Id = 0x672 Stepping = 2 Features=0x387fbff real memory = 268369920 (262080K bytes) config> q avail memory = 257515520 (251480K bytes) Programming 24 pins in IOAPIC #0 IOAPIC #0 intpin 2 -> irq 0 FreeBSD/SMP: Multiprocessor motherboard cpu0 (BSP): apic id: 1, version: 0x00040011, at 0xfee00000 cpu1 (AP): apic id: 0, version: 0x00040011, at 0xfee00000 io0 (APIC): apic id: 2, version: 0x00170011, at 0xfec00000 Preloaded elf kernel "kernel" at 0xc02c5000. Preloaded userconfig_script "/boot/kernel.conf" at 0xc02c509c. Pentium Pro MTRR support enabled md0: Malloc disk npx0: on motherboard npx0: INT 16 interface pcib0: on motherboard pci0: on pcib0 [snip] isab0: at device 18.0 on pci0 isa0: on isab0 pci0: at 18.1 pci0: at 18.2 irq 10 Timecounter "PIIX" frequency 3579545 Hz /Jesper -- Jesper Skriver, jesper(at)skriver(dot)dk - CCIE #5456 Work: Network manager @ AS3292 (Tele Danmark DataNetworks) Private: Geek @ AS2109 (A much smaller network ;-) One Unix to rule them all, One Resolver to find them, One IP to bring them all and in the zone to bind them. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message