From owner-freebsd-hackers@FreeBSD.ORG Sat Oct 4 12:03:01 2003 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 3514D16A4B3 for ; Sat, 4 Oct 2003 12:03:01 -0700 (PDT) Received: from obsecurity.dyndns.org (adsl-64-169-107-253.dsl.lsan03.pacbell.net [64.169.107.253]) by mx1.FreeBSD.org (Postfix) with ESMTP id C03E743FFD for ; Sat, 4 Oct 2003 12:02:59 -0700 (PDT) (envelope-from kris@obsecurity.org) Received: from rot13.obsecurity.org (rot13.obsecurity.org [10.0.0.5]) by obsecurity.dyndns.org (Postfix) with ESMTP id E738266C9E; Sat, 4 Oct 2003 12:02:51 -0700 (PDT) Received: by rot13.obsecurity.org (Postfix, from userid 1000) id 263A1A88; Sat, 4 Oct 2003 12:02:52 -0700 (PDT) Date: Sat, 4 Oct 2003 12:02:52 -0700 From: Kris Kennaway To: Mikulas Patocka Message-ID: <20031004190251.GA60026@rot13.obsecurity.org> References: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="C7zPtVaVf+AK4Oqc" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i cc: freebsd-hackers@freebsd.org Subject: Re: Hyperthreading slowdown X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 04 Oct 2003 19:03:01 -0000 --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--