From owner-freebsd-emulation@FreeBSD.ORG Fri Mar 4 17:46:46 2011 Return-Path: Delivered-To: freebsd-emulation@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 3AED11065670; Fri, 4 Mar 2011 17:46:46 +0000 (UTC) (envelope-from dchagin@dchagin.static.corbina.ru) Received: from contrabass.post.ru (contrabass.post.ru [85.21.78.5]) by mx1.freebsd.org (Postfix) with ESMTP id DB8228FC13; Fri, 4 Mar 2011 17:46:45 +0000 (UTC) Received: from corbina.ru (mail.post.ru [195.14.50.16]) by contrabass.post.ru (Postfix) with ESMTP id D3E1BC9F8B; Fri, 4 Mar 2011 20:46:42 +0300 (MSK) X-Virus-Scanned: by cgpav Uf39PSi9pFi9oFi9 Received: from [10.208.17.3] (HELO dchagin.static.corbina.ru) by corbina.ru (CommuniGate Pro SMTP 5.1.14) with ESMTPS id 305839262; Fri, 04 Mar 2011 20:46:42 +0300 Received: from dchagin.static.corbina.ru (localhost [127.0.0.1]) by dchagin.static.corbina.ru (8.14.4/8.14.4) with ESMTP id p24HkgiG008571; Fri, 4 Mar 2011 20:46:42 +0300 (MSK) (envelope-from dchagin@dchagin.static.corbina.ru) Received: (from dchagin@localhost) by dchagin.static.corbina.ru (8.14.4/8.14.4/Submit) id p24HkbLm008570; Fri, 4 Mar 2011 20:46:37 +0300 (MSK) (envelope-from dchagin) Date: Fri, 4 Mar 2011 20:46:37 +0300 From: Chagin Dmitry To: Alexander Best Message-ID: <20110304174637.GA8522@dchagin.static.corbina.ru> References: <20110303212051.GA54978@freebsd.org> <20110304061328.GA4073@dchagin.static.corbina.ru> <20110304110843.GA65337@freebsd.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="BOKacYhQ+x31HxR3" Content-Disposition: inline In-Reply-To: <20110304110843.GA65337@freebsd.org> User-Agent: Mutt/1.5.21 (2010-09-15) Cc: freebsd-emulation@freebsd.org Subject: Re: regarding issues with futexes and multiple threads X-BeenThere: freebsd-emulation@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Development of Emulators of other operating systems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 04 Mar 2011 17:46:46 -0000 --BOKacYhQ+x31HxR3 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Mar 04, 2011 at 11:08:43AM +0000, Alexander Best wrote: > On Fri Mar 4 11, Chagin Dmitry wrote: > > On Thu, Mar 03, 2011 at 09:20:51PM +0000, Alexander Best wrote: > > > hi there, > > >=20 > > > i've been investigating this issue for quite a while now and simply w= anted to > > > post some measurements i did. > > >=20 > > > basically there's a massive slowdown when a process triggers a lot of= threads > > > which are doing futex operations. the following example is from darre= n hart's > > > futex test suite (performance/). the slowdown seems to SMP related. h= ere are > > > the measurements running with SMP enabled and with kern.smp.disabled= =3D1: > > >=20 > >=20 > > 1) slowdown is expected behaviour. >=20 > even if the slowdown is to be expected, looking at the screenshot with the > top(1) output it seems obvious that there are issues with the current fut= ex > implementation. >=20 why do you think it's a problem with the futexes? > > 2) is it possible to run this test suite on FreeBSD? >=20 > i used emulators/linux_dist-gentoo-stage3 to compile the testsuite and th= en ran > it natively under freebsd. if you want to i can send you the file. it's >=20 > futex_wait: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dyn= amically linked (uses shared libs), for GNU/Linux 2.6.9, not stripped >=20 ah, tests directly calls sys_futex syscall, so can't be used for umtx/futex= comparison :) It would be great to have the same set of tests to compare the linuxulator = threads and the native. --=20 Have fun! chd --BOKacYhQ+x31HxR3 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (FreeBSD) iEYEARECAAYFAk1xJXwACgkQ0t2Tb3OO/O1S9ACff7qrg5ZZXjV/eZEsQPbg5qdW YzEAoI2Zgk/MyNnIROTap6wsuqjwcXbO =agI7 -----END PGP SIGNATURE----- --BOKacYhQ+x31HxR3--