Date: Sat, 4 Oct 2003 12:02:52 -0700 From: Kris Kennaway <kris@obsecurity.org> To: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Cc: freebsd-hackers@freebsd.org Subject: Re: Hyperthreading slowdown Message-ID: <20031004190251.GA60026@rot13.obsecurity.org> In-Reply-To: <Pine.LNX.4.58.0310041623250.6065@artax.karlin.mff.cuni.cz> References: <Pine.LNX.4.58.0310041623250.6065@artax.karlin.mff.cuni.cz>
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--C7zPtVaVf+AK4Oqc Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Oct 04, 2003 at 04:39:03PM +0200, Mikulas Patocka wrote: > Hi >=20 > I installed FreeBSD 4.9RC1 on P4 3GHz with hyperthreading and I see > drastic slowdown when kernel with hyperthreading is booted. For example > program compilation took this time: >=20 > hyperthreading kernel, make -j 1 --- 1:09 > hyperthreading kernel, make -j 2 --- 0:42 > singlethreading kernel, make -j 1 --- 0:45 > singlethreading kernel, make -j 2 --- 0:41 >=20 > Compilation does very few system calls so when I compile with only one > process (-j 1), it should be as fast as with singlethreading kernel. Do > you have any idea why is it so slow? Do you realise that hyperthreading !=3D a secret extra CPU in your system? Kris --C7zPtVaVf+AK4Oqc Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (FreeBSD) iD8DBQE/fxlbWry0BWjoQKURAoSJAJ0Up/hgcoIghVZ94g0wS3E05SemqwCgrVW0 vmx8fz6AFu9oKRYpNs2b1kM= =2WqZ -----END PGP SIGNATURE----- --C7zPtVaVf+AK4Oqc--
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