Date: Fri, 13 Oct 2006 16:13:21 -0400 From: Kris Kennaway <kris@obsecurity.org> To: Chuck Swiger <cswiger@mac.com> Cc: freebsd-performance@FreeBSD.ORG, Kris Kennaway <kris@obsecurity.org>, Eric Hodel <drbrain@segment7.net> Subject: Re: Help with improving mysql performance on 6.2PRE Message-ID: <20061013201321.GA774@xor.obsecurity.org> In-Reply-To: <9500A2C9-07EB-4EEA-9477-9E6B4BFEB437@mac.com> References: <3731.71.56.92.181.1160009571.squirrel@www.stelesys.com> <200610120925.k9C9PmUK048690@lurza.secnetix.de> <20061012205342.GA62241@xor.obsecurity.org> <A2430386-EB9D-4AEE-9144-F7D53D84A9F0@segment7.net> <9500A2C9-07EB-4EEA-9477-9E6B4BFEB437@mac.com>
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--/9DWx/yDrRhgMJTb Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Oct 13, 2006 at 11:49:04AM -0700, Chuck Swiger wrote: > On Oct 13, 2006, at 11:26 AM, Eric Hodel wrote: > >>>Or did that change recently? > >> > >>It's only on certain systems, apparently. > > > >Is there a list of systems where it is safe to use the TSC with =20 > >SMP? Or some script we can run? >=20 > The problem of the TSC clocks getting out of sync affects pretty much =20 > all AMD X2 dual-core CPUs, as well as the older 32-bit Althon MP =20 > CPUs; the Intel Xeon and Core Duo CPUs seem to do a lot better, =20 > although older Intel CPUs have also been reported to show problems =20 > with the TSC. >=20 > Disabling the fancy power-management capabilities (SpeedStep, =20 > PowerNow, Cool-n-quiet) to prevent the system from adjusting the CPU =20 > clock frequencies seems to reduce the extent of the problem. =20 > However, if you want your system clock to work reliably, using the =20 > ACPI-safe or i8254 timecounters is going to do much better than using =20 > the faster-but-unreliable TSC method. Beyond that, just see if it works ;-) Kris --/9DWx/yDrRhgMJTb Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (FreeBSD) iD8DBQFFL/NgWry0BWjoQKURAlQ/AJ9GPXFiWr7wZDw+YLm2B3nV5XqWqwCfQkMS FEatqEPd4xFA++6nUFV6PWc= =0MD/ -----END PGP SIGNATURE----- --/9DWx/yDrRhgMJTb--
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