From owner-freebsd-hackers@FreeBSD.ORG Thu Jan 27 21:35:41 2011 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8E725106566C for ; Thu, 27 Jan 2011 21:35:41 +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 11A118FC21 for ; Thu, 27 Jan 2011 21:35:40 +0000 (UTC) Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id p0RLZaLO099304 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 27 Jan 2011 23:35:36 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.4/8.14.4) with ESMTP id p0RLZaPH053875; Thu, 27 Jan 2011 23:35:36 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.4/8.14.4/Submit) id p0RLZasv053874; Thu, 27 Jan 2011 23:35:36 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Thu, 27 Jan 2011 23:35:36 +0200 From: Kostik Belousov To: Devin Teske Message-ID: <20110127213536.GR2518@deviant.kiev.zoral.com.ua> References: <20110125234911.223d8f75@kan.dnsalias.net> <201101271305.21510.naylor.b.david@gmail.com> <20110127203126.GN2518@deviant.kiev.zoral.com.ua> <1296161448.20060.40.camel@dt.vicor.com> <20110127205907.GP2518@deviant.kiev.zoral.com.ua> <1296162754.20060.42.camel@dt.vicor.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="PI2T0JrbAUafY2qi" Content-Disposition: inline In-Reply-To: <1296162754.20060.42.camel@dt.vicor.com> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: clamav-milter 0.95.2 at skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-3.4 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00, DNS_FROM_OPENWHOIS autolearn=no version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua Cc: freebsd-hackers@freebsd.org, Mark Saad Subject: Re: rtld optimizations X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 27 Jan 2011 21:35:41 -0000 --PI2T0JrbAUafY2qi Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jan 27, 2011 at 09:12:34PM +0000, Devin Teske wrote: > On Thu, 2011-01-27 at 22:59 +0200, Kostik Belousov wrote: >=20 > > On Thu, Jan 27, 2011 at 08:50:48PM +0000, Devin Teske wrote: > > > Probably did something like this: > > >=20 > > > time sh -c '( firefox & ); sleep 10000000' > > >=20 > > > and then pressed Ctrl-C when he felt that firefox was finished loadin= g. > > > The moment Ctrl-C is pressed, time(1) shows how long it ran up until = you > > > pressed Ctrl-C. > > > NOTE: Pressing Ctrl-C will not terminate the firefox instance. > >=20 > > You cannot have 1/100 of seconds precision with this method. > > This is why I am asking, seeing < 0.1 seconds difference. > > Not to mention some methodical questions, like whether the caches were > > warmed before the measurement by several runs before the actual > > test. >=20 >=20 > Really? >=20 > $ time sh -c '( firefox & ); sleep 10000000' > ^C >=20 > real 0m5.270s > user 0m0.000s > sys 0m0.005s >=20 >=20 > I'd call that 1/100th of a second precision, wouldn't you? >=20 > HINT: Try using bash instead of csh. (I supposed that) obvious point of my mail is that you cannot reliably measure 1/100 second intervals when human interaction is involved. To make it completely obvious: human has to press CTRL-C, I did not mean reading the numbers from display. --PI2T0JrbAUafY2qi Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (FreeBSD) iEYEARECAAYFAk1B5SgACgkQC3+MBN1Mb4iyEACcDA+e2npfczgWpJsikfv1yXNA hW4AmgI+O15s0tDj/nW8abxKYCsdbGOD =EDM/ -----END PGP SIGNATURE----- --PI2T0JrbAUafY2qi--