From owner-freebsd-arch@FreeBSD.ORG Thu Dec 14 11:37:41 2006 Return-Path: X-Original-To: freebsd-arch@FreeBSD.org Delivered-To: freebsd-arch@FreeBSD.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id B38A916A415; Thu, 14 Dec 2006 11:37:41 +0000 (UTC) (envelope-from avg@icyb.net.ua) Received: from citadel.icyb.net.ua (citadel.icyb.net.ua [212.40.38.140]) by mx1.FreeBSD.org (Postfix) with ESMTP id 02CC043C9D; Thu, 14 Dec 2006 11:36:02 +0000 (GMT) (envelope-from avg@icyb.net.ua) Received: from [212.40.38.87] (oddity-e.topspin.kiev.ua [212.40.38.87]) by citadel.icyb.net.ua (8.8.8p3/ICyb-2.3exp) with ESMTP id NAA17946; Thu, 14 Dec 2006 13:37:35 +0200 (EET) (envelope-from avg@icyb.net.ua) Message-ID: <4581377E.2090407@icyb.net.ua> Date: Thu, 14 Dec 2006 13:37:34 +0200 From: Andriy Gapon User-Agent: Thunderbird 1.5.0.8 (X11/20061113) MIME-Version: 1.0 To: Peter Wemm , freebsd-arch@FreeBSD.org Content-Type: text/plain; charset=KOI8-U Content-Transfer-Encoding: 7bit Cc: Subject: HZ of 1024 X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 14 Dec 2006 11:37:41 -0000 Peter and all, I am playing with an idea of using RTC/IRQ8 instead of 8254 timer/IRQ0 to drive system hard clock. Due to the nature of RTC, if I got it correctly, I think I will have to use HZ of 1024 (or some reasonable divisor of it). I've accidentally noticed that 1024 was used as a default value of hz on amd64 systems for a while, but then it was changed to use 1000. I've read the cvs commit logs about some interference with stat clock and/or prof clock, but I couldn't dig up any detailed information about this. Could you please share your experience about hz=1024 and advise what I should look for ? Maybe you even have some ideas on how to eliminate or reduce the interference ? Thank you. -- Andriy Gapon