From owner-freebsd-current@FreeBSD.ORG Sat Sep 22 11:20:30 2012 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 3527F106566B; Sat, 22 Sep 2012 11:20:30 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.zoral.com.ua (mx0.zoral.com.ua [91.193.166.200]) by mx1.freebsd.org (Postfix) with ESMTP id A60988FC12; Sat, 22 Sep 2012 11:20:27 +0000 (UTC) Received: from skuns.kiev.zoral.com.ua (localhost [127.0.0.1]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id q8MBKQJL084821; Sat, 22 Sep 2012 14:20:26 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.5/8.14.5) with ESMTP id q8MBKEYG072729; Sat, 22 Sep 2012 14:20:14 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.5/8.14.5/Submit) id q8MBKEpk072728; Sat, 22 Sep 2012 14:20:14 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Sat, 22 Sep 2012 14:20:14 +0300 From: Konstantin Belousov To: Dimitry Andric Message-ID: <20120922112014.GH37286@deviant.kiev.zoral.com.ua> References: <505CDE9C.3060504@andric.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="inJ2Z4oiSrNaWWYu" Content-Disposition: inline In-Reply-To: <505CDE9C.3060504@andric.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Virus-Scanned: clamav-milter 0.95.2 at skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-4.0 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua Cc: freebsd-current@freebsd.org, freebsd-toolchain@freebsd.org Subject: Re: More kernel performance tests on FreeBSD 10.0-CURRENT X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 22 Sep 2012 11:20:30 -0000 --inJ2Z4oiSrNaWWYu Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Sep 21, 2012 at 11:39:40PM +0200, Dimitry Andric wrote: > Hi all, >=20 > As a followup to my previous post about the performance of FreeBSD 10.0 > kernels compiled with different compilers (clang and gcc), I did another > series of tests, now on a more modern machine (Core i5-based). I also > tested the performance with different compiler optimization settings. >=20 > The attached text file[1] contains more information about these tests, > performance data, and my conclusions. Any errors and omissions are also > my fault, so if you notice them, please let me know. >=20 > The executive summary: GENERIC kernels compiled with clang 3.2 are again > a little faster than those compiled with gcc 4.2.1. For gcc, compiling > with -O2 also gives a slightly faster kernel than with -O1, but for > clang there is no measurable difference between those flags. >=20 > Again, many thanks to Gavin Atkinson for providing the required > hardware. =2E.. > Conclusion: > ----------- > Kernels compiled with clang are a little faster in real time for building= world, > and in system time the difference is even larger, roughly 10%. For clang= , the > difference between -O1 and -O2 is not measurable, but for gcc, -O2 is sli= ghtly > faster than -O1. >=20 Thank you very much for finishing the initial assessment. In my opinion, this positively closes the issue of the uncertainicity of the performance impact of the proposed clang use by default for the base system. Now, if only ports were handled. --inJ2Z4oiSrNaWWYu Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (FreeBSD) iEYEARECAAYFAlBdnu4ACgkQC3+MBN1Mb4iCMgCgmdqw2MEIuQsM0v0HE9aoCKg6 /lkAoJhA1D5iqf3kTQ4+cLKdal+ARYtW =qZBX -----END PGP SIGNATURE----- --inJ2Z4oiSrNaWWYu--