From owner-freebsd-current Fri Jan 31 10:25: 1 2003 Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id B8E8537B401 for ; Fri, 31 Jan 2003 10:24:59 -0800 (PST) Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5D0DF43F43 for ; Fri, 31 Jan 2003 10:24:59 -0800 (PST) (envelope-from dillon@apollo.backplane.com) Received: from apollo.backplane.com (localhost [127.0.0.1]) by apollo.backplane.com (8.12.6/8.12.6) with ESMTP id h0VIOt0i095381; Fri, 31 Jan 2003 10:24:56 -0800 (PST) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.12.6/8.12.6/Submit) id h0VIOtmF095380; Fri, 31 Jan 2003 10:24:55 -0800 (PST) Date: Fri, 31 Jan 2003 10:24:55 -0800 (PST) From: Matthew Dillon Message-Id: <200301311824.h0VIOtmF095380@apollo.backplane.com> To: Trish Lynch Cc: freebsd-current@FreeBSD.ORG Subject: Re: Hyperthreading and machdep.cpu_idle_hlt References: <20030131125804.E1357-100000@femme> Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG :So, at the request of bmilekic, I ran netpipe on a hyperthreading box (non :hyperthreading, I'll do when I can turn it off in BIOS next time I'm down :there) :... : :The results are here: : :http://bsdunix.net/performance : :all information on what command line options I used is in there. : :the difference with it on is pretty substantial, might be worth noting in :tuning(7) : :-Trish : :-- :Trish Lynch trish@bsdunix.net Those results are indeed quite substantial. Before you modify tuning(7), though, lets wait a bit to see if anyone comes up with a fix to the performance issue when idle_hlt is turned off. In particular I would like to try using a per-cpu global test in the idle loop that avoids doing any locked bus cycles. Unfortunately I am not sure if I have any hyperthreading capable boxes. My primary machine is a pentium 4 but it is running -stable. Timecounter "i8254" frequency 1193182 Hz Timecounter "TSC" frequency 1296069572 Hz CPU: Pentium 4 (1296.07-MHz 686-class CPU) Origin = "GenuineIntel" Id = 0xf07 Stepping = 7 Features=0x3febf9ff,ACC> It has HTT set but it's only a 1.2GHz box and I heard somewhere that only 2+ GHz P4's had hyperthreading. I noticed some MFCs to stable that suggested hyperthreading support but I do not know if full hyperthreading support has been MFCd yet or is intended to be MFCd to -stable. -Matt Matthew Dillon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message