Date: Fri, 28 Nov 2003 18:51:37 -0800 From: Kris Kennaway <kris@obsecurity.org> To: "Marc G. Fournier" <scrappy@hub.org> Cc: freebsd-stable@freebsd.org Subject: Re: Time jumping on both 4.x and 5.x ... Message-ID: <20031129025137.GA92629@xor.obsecurity.org> In-Reply-To: <20031128212342.G99096@ganymede.hub.org> References: <20031128212342.G99096@ganymede.hub.org>
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--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--
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