From owner-freebsd-stable@FreeBSD.ORG Fri Nov 28 18:51:38 2003 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id D6BB316A4CE; Fri, 28 Nov 2003 18:51:38 -0800 (PST) Received: from obsecurity.dyndns.org (adsl-63-207-60-234.dsl.lsan03.pacbell.net [63.207.60.234]) by mx1.FreeBSD.org (Postfix) with ESMTP id BE61943FD7; Fri, 28 Nov 2003 18:51:37 -0800 (PST) (envelope-from kris@obsecurity.org) Received: by obsecurity.dyndns.org (Postfix, from userid 1000) id 6A08266C8E; Fri, 28 Nov 2003 18:51:37 -0800 (PST) Date: Fri, 28 Nov 2003 18:51:37 -0800 From: Kris Kennaway To: "Marc G. Fournier" Message-ID: <20031129025137.GA92629@xor.obsecurity.org> References: <20031128212342.G99096@ganymede.hub.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="wac7ysb48OaltWcw" Content-Disposition: inline In-Reply-To: <20031128212342.G99096@ganymede.hub.org> User-Agent: Mutt/1.4.1i cc: freebsd-current@freebsd.org cc: freebsd-stable@freebsd.org Subject: Re: Time jumping on both 4.x and 5.x ... X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 29 Nov 2003 02:51:39 -0000 --wac7ysb48OaltWcw Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Nov 28, 2003 at 09:32:30PM -0400, Marc G. Fournier wrote: >=20 > In trying to isolate an issue where the PostgreSQL 'explain analyze' is > showing "odd results" (namely, negative time estimates on queries), Tom > Lane wrote a quick C program to test gettimeofday() (program attached) ... > the results on a 4.9-PRERELEASE kernel of Sep 20 14:16:48 ADT 2003 shows: >=20 > neptune# time ./timetest > out of order tv_sec: 1070068479 99040, prev 1070069174 725235 > out of order tv_usec: 1070068479 99040, prev 1070069174 725235 > out of order tv_sec: 1070069175 19687, prev 1070068479 99040 > out of order tv_usec: 1070069175 19687, prev 1070068479 99040 > out of order tv_sec: 1070068499 99377, prev 1070069194 625573 > out of order tv_usec: 1070068499 99377, prev 1070069194 625573 > out of order tv_sec: 1070069194 808542, prev 1070068499 99377 > ^C1.171u 23.461s 0:24.68 99.7% 5+169k 1+0io 0pf+0w >=20 > One person on the list has tried the same script on a 5.2 kernel, and > reports seeing similar results, but after a longer period of time (~30min) > ... What hardware, kernel configuration, etc? Do you have a misconfigured ntpd/timed that is manually flapping the time around? I've run that test for a few minutes on 4.9 without problems. Kris --wac7ysb48OaltWcw Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (FreeBSD) iD8DBQE/yAm5Wry0BWjoQKURArUCAJ9HVLrZkp9QWmU+FWGzFtjhbko+JgCeKCMX lch+xmXssnI/4RTUF5WpaAc= =X7bg -----END PGP SIGNATURE----- --wac7ysb48OaltWcw--