Date: Fri, 27 Jun 2003 16:53:47 -0700 From: Brooks Davis <brooks@one-eyed-alien.net> To: Doug White <dwhite@gumbysoft.com>, current@freebsd.org Subject: Re: Hyperthreading Message-ID: <20030627235347.GC7217@Odin.AC.HMC.Edu> In-Reply-To: <20030627233912.GA90348@gforce.johnson.home> References: <20030627181836.GA81335@node1.cluster.srrc.usda.gov> <20030627154252.X5016@carver.gumbysoft.com> <20030627233912.GA90348@gforce.johnson.home>
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--hOcCNbCCxyk/YU74 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Jun 27, 2003 at 06:39:12PM -0500, Glenn Johnson wrote: > Thanks. I had read the smp manual page. I know _how_ to enable HTT; I > was wondering whether I _should_ enable it. It seems the answer is that > it is not beneficial in its current state because the scheduler does not > yet differentiate between physical and logical processors. It's more complicated then that. For many users, it's true that HTT is not useful due to the scheduling issues, but for some applications where you keep all the CPUs busy, it does help. Somewhat suprisingly, SETI@Home performs better with HTT enabled then without. The individual workunits take longer to process, but the overall throughput is better (4 workunits every 6hrs instead of 2 workunits every 4hrs). -- Brooks --=20 Any statement of the form "X is the one, true Y" is FALSE. PGP fingerprint 655D 519C 26A7 82E7 2529 9BF0 5D8E 8BE9 F238 1AD4 --hOcCNbCCxyk/YU74 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQE+/NkKXY6L6fI4GtQRApx0AJ9U3A1uP9+Z4tkZham7jATmbDtGTACfeuWf NScqmaje94ydTxqosO1yqKU= =LKEI -----END PGP SIGNATURE----- --hOcCNbCCxyk/YU74--
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