From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754543AbaELIre (ORCPT ); Mon, 12 May 2014 04:47:34 -0400 Received: from casper.infradead.org ([85.118.1.10]:33860 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753450AbaELIrd (ORCPT ); Mon, 12 May 2014 04:47:33 -0400 Date: Mon, 12 May 2014 10:47:27 +0200 From: Peter Zijlstra To: "Michael Kerrisk (man-pages)" Cc: Juri Lelli , Dario Faggioli , Ingo Molnar , lkml , Dave Jones Subject: Re: [BUG] sched_setattr() SCHED_DEADLINE hangs system Message-ID: <20140512084727.GN30445@twins.programming.kicks-ass.net> References: <536F8F0E.7020301@gmail.com> <53707007.3080003@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="wdXZ0KDsOFX3OpPb" Content-Disposition: inline In-Reply-To: <53707007.3080003@gmail.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --wdXZ0KDsOFX3OpPb Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, May 12, 2014 at 08:53:59AM +0200, Michael Kerrisk (man-pages) wrote: > On 05/11/2014 04:54 PM, Michael Kerrisk (man-pages) wrote: > > $ time sudo ./t_sched_setattr d 18446744072 18446744072 18446744073 >=20 > I realize my speculation was completely off the mark. time(2) really=20 > is reporting the truth, and the sched_setattr() call returns immediately. > But it looks like with these settings the deadline scheduler gets itself > into a confused state. The process chews up a vast amount of CPU time > for the few actions (including process teardown) that occur after > the sched_setattr() call, and since the SCHED_DEADLINE process has > priority over everything else, the system locks up. Yeah, its doing something weird alright.. let me see if I can get something useful out. Btw, you do know about EX_USAGE from sysexits.h ? --wdXZ0KDsOFX3OpPb Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJTcIqfAAoJEHZH4aRLwOS68IcQAJULAP+kL6DF6Dm/hSg59H84 E6LZwqzJEcpQfstZC09vgjRYFNy1FBaAkzFRB+ZZFdMH1MelS425AGWSh7Kjpzrw ERTRvA4GLS9Tkg7H07zGp07zF5aq1xVOpCAJXlbFhTXX3+S9O9JEd56rEb5p+APx vF3ecCJIKpLzQvuWC/9xvxDc5xPbq+B0Q9JiL0NicIHbeZZHOAas6DCbEuENud34 zGLMkogLmaLGjmXPfBPa/2MT1goZI9qNFe+GBoLimNw+in6m7JAh+mksb2aXu7Ax eUhsBdNq4kj0Qw7eD0HWkSPTm48Jtdd5SDGkVbuUWPWCkDXdNqPXowdVS1rnawLo IYjL1k/9bbF3TvJMdM9ktN+eJ8+DEyn7gPfyEbHGFfo86dgcIGkOOBd/k4MwUxB7 J3surJPaGueGDX6/Y8h+ZfIVTuD+Mx5DqqcQsb4HC8gVlA0Xk/7UoWnD1UjBhNol RMNh3ladksUUgVnVk8cIN4i85qH5ZxjW3IxvuZDFuSZ6TamE+nU96JQlA6/JVYai 6liQ0sQz2BE7MhHxNTvD1J4QbXUzwI9njxIi/dt+H95Ww2yWRhxlh3DA7KsKUeJH B++hSbyT5bGkd53XSWzUPqTa1e55V3/EZg0vKr8XRiXntfBeHBJUedplgr9xPKEG da1vVELlcraSKPxLikA5 =9X1x -----END PGP SIGNATURE----- --wdXZ0KDsOFX3OpPb--