From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.saout.de ([127.0.0.1]) by localhost (mail.saout.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id awfWoHoRDz4e for ; Sun, 16 Dec 2012 23:02:29 +0100 (CET) Received: from plane.gmane.org (plane.gmane.org [80.91.229.3]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.saout.de (Postfix) with ESMTPS for ; Sun, 16 Dec 2012 23:02:29 +0100 (CET) Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1TkMIC-0006zr-2C for dm-crypt@saout.de; Sun, 16 Dec 2012 23:02:40 +0100 Received: from d67-193-232-12.home3.cgocable.net ([67.193.232.12]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sun, 16 Dec 2012 23:02:40 +0100 Received: from brian by d67-193-232-12.home3.cgocable.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sun, 16 Dec 2012 23:02:40 +0100 From: "Brian J. Murrell" Date: Sun, 16 Dec 2012 17:02:18 -0500 Message-ID: <50CE44EA.5080009@interlinx.bc.ca> References: <50CE3C33.2040900@gmail.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig62F9B57B86D6D60A2A8EBA09" In-Reply-To: <50CE3C33.2040900@gmail.com> Subject: Re: [dm-crypt] multiple crypt devices not using multiple CPUs List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: dm-crypt@saout.de This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig62F9B57B86D6D60A2A8EBA09 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 12-12-16 04:25 PM, Milan Broz wrote: >=20 > In current kernels, work keeps on cpu which submitted it. So a single process doing parallel reads from multiple devices (I'm sure you could guess where I'm going with this) will never see more throughput than it would from a single device? If so, all the more reason to get multi-core support (for a single process of course) involved. :-/ > Please read > http://www.saout.de/pipermail/dm-crypt/2012-July/002582.html Yeah. I'm trying to see this "more processes" behavior but even the two dds each running in different shells are still attacking the same core. > (and try to run the second case with direct-io, iow add oflag=3Ddirect = for dd) oflag=3Ddirect? # dd oflag=3Ddirect of=3D/dev/null if=3D/dev/mapper/t1-use bs=3D1M count=3D= 1000 dd: opening =91/dev/null=92: Invalid argument I guess O_DIRECT it not valid for /dev/null. Cheers, b. --------------enig62F9B57B86D6D60A2A8EBA09 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with undefined - http://www.enigmail.net/ iEYEARECAAYFAlDOROoACgkQl3EQlGLyuXA0rACgjGSIZ4z26p+K/XZV4Rwe4CnZ NEoAn3H4Lm2ZtMQtev5subPWPxxotYNo =fmza -----END PGP SIGNATURE----- --------------enig62F9B57B86D6D60A2A8EBA09--