From owner-freebsd-questions@FreeBSD.ORG Tue Nov 29 19:01:16 2011 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 17602106566C for ; Tue, 29 Nov 2011 19:01:16 +0000 (UTC) (envelope-from ipluta@wp.pl) Received: from mx4.wp.pl (mx4.wp.pl [212.77.101.8]) by mx1.freebsd.org (Postfix) with ESMTP id 87E948FC18 for ; Tue, 29 Nov 2011 19:01:15 +0000 (UTC) Received: (wp-smtpd smtp.wp.pl 21655 invoked from network); 29 Nov 2011 19:34:34 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=wp.pl; s=1024a; t=1322591674; bh=7qW76Ff9oPPfNq7/WrK4+nQ4opdfwg8uMOuop6dYZNI=; h=From:To:Subject; b=VuMK9MVTMZT0iwf8VYcLC9rP5Eufp1b/9CPAv0N5LE6+2Tzdp3Fn+ZPWqQK/uiwqw SsTzGyK3tXbej9FSvgjucXLP1FnY/nD60QVT3rw/Zk8CokQ03zjAj2DsHCfLDfG6Yu 3iqnmYCH9yMu4LyM5x7dWrh5HFdS9XAq2BBOEpVQ= Received: from aays10.neoplus.adsl.tpnet.pl (HELO [10.0.0.114]) (ipluta@[83.6.130.10]) (envelope-sender ) by smtp.wp.pl (WP-SMTPD) with AES256-SHA encrypted SMTP for ; 29 Nov 2011 19:34:34 +0100 Message-ID: <4ED525B1.3010100@wp.pl> Date: Tue, 29 Nov 2011 19:34:25 +0100 From: Ireneusz Pluta User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:8.0) Gecko/20111105 Thunderbird/8.0 MIME-Version: 1.0 To: freebsd-questions@freebsd.org Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-WP-AV: skaner antywirusowy poczty Wirtualnej Polski S. A. X-WP-SPAM: NO 0000000 [4bM0] Subject: kern.timecounter.hardware change on the fly X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 29 Nov 2011 19:01:16 -0000 Hi all, is it safe to change kern.timecounter.hardware on a busy production system on the fly? Or I better schedule a downtime to do that? It seems I got a bad current selection, somehow, probably as an effect of leaving /etc/sysctl.conf contents of early experimental setup stage of this machine. $ sysctl -a | grep timecounter kern.timecounter.tick: 1 kern.timecounter.choice: TSC(-100) HPET(900) ACPI-fast(1000) i8254(0) dummy(-1000000) kern.timecounter.hardware: i8254 kern.timecounter.stepwarnings: 0 kern.timecounter.tc.i8254.mask: 65535 kern.timecounter.tc.i8254.counter: 23813 kern.timecounter.tc.i8254.frequency: 1193182 kern.timecounter.tc.i8254.quality: 0 kern.timecounter.tc.ACPI-fast.mask: 16777215 kern.timecounter.tc.ACPI-fast.counter: 4619803 kern.timecounter.tc.ACPI-fast.frequency: 3579545 kern.timecounter.tc.ACPI-fast.quality: 1000 kern.timecounter.tc.HPET.mask: 4294967295 kern.timecounter.tc.HPET.counter: 1703441786 kern.timecounter.tc.HPET.frequency: 14318180 kern.timecounter.tc.HPET.quality: 900 kern.timecounter.tc.TSC.mask: 4294967295 kern.timecounter.tc.TSC.counter: 2720513805 kern.timecounter.tc.TSC.frequency: 2266656152 kern.timecounter.tc.TSC.quality: -100 kern.timecounter.smp_tsc: 0 kern.timecounter.invariant_tsc: 1 This setting seems to affect what is generally described here: http://archives.postgresql.org/pgsql-admin/2011-01/msg00059.php and this is the primary reason I want to change. Should I switch to HPET or ACPI-fast?