From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752368AbaE1K7H (ORCPT ); Wed, 28 May 2014 06:59:07 -0400 Received: from casper.infradead.org ([85.118.1.10]:42217 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751441AbaE1K7G (ORCPT ); Wed, 28 May 2014 06:59:06 -0400 Date: Wed, 28 May 2014 12:58:55 +0200 From: Peter Zijlstra To: Vincent Guittot Cc: mingo@kernel.org, linux-kernel@vger.kernel.org, linux@arm.linux.org.uk, linux-arm-kernel@lists.infradead.org, preeti@linux.vnet.ibm.com, Morten.Rasmussen@arm.com, efault@gmx.de, nicolas.pitre@linaro.org, linaro-kernel@lists.linaro.org, daniel.lezcano@linaro.org Subject: Re: [PATCH v2 09/11] sched: test the cpu's capacity in wake affine Message-ID: <20140528105855.GR30445@twins.programming.kicks-ass.net> References: <1400860385-14555-1-git-send-email-vincent.guittot@linaro.org> <1400860385-14555-10-git-send-email-vincent.guittot@linaro.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="iXtk48AVKREFnTks" Content-Disposition: inline In-Reply-To: <1400860385-14555-10-git-send-email-vincent.guittot@linaro.org> 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 --iXtk48AVKREFnTks Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, May 23, 2014 at 05:53:03PM +0200, Vincent Guittot wrote: > Currently the task always wakes affine on this_cpu if the latter is idle. > Before waking up the task on this_cpu, we check that this_cpu capacity is= not > significantly reduced because of RT tasks or irq activity. >=20 > Use case where the number of irq and the time spent under irq is important > will take benefit of this because the task that is woken up by irq or sof= tirq > will not use the same CPU than irq (and softirq) but a idle one which sha= re > its LLC. OK, so I'm having a terrible time parsing the above. So looking at the patch you make balance false even when this_load=3D=3D0 when the effective power/capacity (nico's patches haven't fully sunk in yet) of this cpu is less than that of the previous cpu. Is that right? Now I'm only struggling to understand the rationale for this, its got LLC in there somewhere, but I'm failing to comprehend. --iXtk48AVKREFnTks Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJThcFvAAoJEHZH4aRLwOS6kTcP+gPsGimv0pTcXcRX2FfYdWiq xIMgJWKEjt8yy8DdDvVJVTKuW46u85oUJBXZ2bWbIK0mQyOKCzWYHheR2JP/RauA 8v3OZU8deAkqXDvUqwkKawrScM5+8X+js+EptNLf2TXMxfh01jUQKC7Fbjzd3wNc opzLXRu5FKePLYOK3mUEf+U0H5D9IbkePV6Oe4M7Zp1cdfY4donyZBHzMF3BIyg6 JzPDpIVBkSjddJ+3yL+zrD6uuqAJ+Ffy9pn47UWfKuuP83s3OysQ5NU9e8OAv7RX rP9yO1InQ7V5Da/IT5jUGctNjP3rrUQfeQiTeSCHVZW5E3Thq2iykT0+UHAVgl6f ZTg9iQMkfv7GwUEs1VHKos9aJfu1mLQypK+n7piHmDx1fTQnHsi6Amd7rr+IlOPD cqbqdo5+KwQAazI2lBqEvYSc0avL2Z1vYGD1YffORoa/3VFo+c3TP+d0XDhbiWzt mnFWK0dMpSufE/4CtmTnw9hR4Zp7sjBJZxghIW4cpWuRjKe6dpnS75k7sOUtI/T5 /Ldc7oXnHLM+r6zBlU3eIyJsbz5Mrk5g/fWK1l1Sa60ctcr6NUBy8pqOqfonKjod z6HpOXBCSQthb18rtmz9M0GKFpC3/MuNGmy5YuN1n+5ZjfA+0S2QEzH81ir6++yN Vyeo69KhpuU/EaDnqiVr =MgS0 -----END PGP SIGNATURE----- --iXtk48AVKREFnTks--