From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rik van Riel Subject: Re: SKL BOOT FAILURE unless idle=nomwait (was Re: PROBLEM: Cpufreq constantly keeps frequency at maximum on 4.5-rc4) Date: Wed, 16 Mar 2016 11:07:16 -0400 Message-ID: <1458140836.14723.30.camel@redhat.com> References: <1458007395.8898.19.camel@redhat.com> <2600831.Qfymhh5Hpv@vostro.rjw.lan> <1458089721.8898.25.camel@redhat.com> <20160316100144.75bfef53@annuminas.surriel.com> <1458139600.14723.29.camel@redhat.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-XKqA/i7U/lNCuixbxF+s" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:54613 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934826AbcCPPHT (ORCPT ); Wed, 16 Mar 2016 11:07:19 -0400 In-Reply-To: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Rafael J. Wysocki" Cc: "Rafael J. Wysocki" , Doug Smythies , Viresh Kumar , Srinivas Pandruvada , "Chen, Yu C" , "linux-pm@vger.kernel.org" , Arto Jantunen , Len Brown --=-XKqA/i7U/lNCuixbxF+s Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2016-03-16 at 16:05 +0100, Rafael J. Wysocki wrote: > On Wed, Mar 16, 2016 at 3:46 PM, Rik van Riel > wrote: > >=20 > > On Wed, 2016-03-16 at 15:14 +0100, Rafael J. Wysocki wrote: > > >=20 > > > On Wed, Mar 16, 2016 at 3:01 PM, Rik van Riel > > > wrote: > > > >=20 > > > >=20 > > > > On the other hand, being more aggressive about C1 allows > > > > other cores to run at higher frequencies... > > > Good point. > > >=20 > > > We need to decide, though. > > >=20 > > > Do we generally want to use more polling or more C1? > > I can see five distinct data points for decision making: > >=20 > > 1) data->next_timer_us where we know for sure the sleep > > =C2=A0=C2=A0=C2=A0interval will be less than C1 latency -> poll > Almost right, modulo my previous comment: that should be the sum of > C1 > exit latency and C1 target residency. Doesn't the residency include the exit latency? After all, we subtract the exit latency from the measured residency time in menu_update. > > Would you like me to write a patch to take the user > > configured latency_req into account, separate out > > the predicted_us and typical_interval, and test whether > > to poll against the smaller of next_timer_us, latency_req, > > and the typical_interval, while we continue to use the > > predicted_us as is in the main selection loop? > Yes, please. Will do. --=20 All Rights Reversed. --=-XKqA/i7U/lNCuixbxF+s Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAABCAAGBQJW6XakAAoJEM553pKExN6DadwH/jT1knpyssmgc1EvABewQtBh v6vq5zaZapCmXnMrJoSZlAHsnSMK3+EMEuL5aktaP27fIi4HDOlULu22jmMhsFP6 6MgV9HOReh0hntYhW3LbnJ/4cCXIiTum3oSLaYh1ods7UGgn+/qZYxZmoR1DbH/r /AlsSs7OW9QKEFQCTefe4DZzgCpd/bZ7GaWDSvrpmaLWwPBlSMFqmajbk0PpC2Rq pzIz6thOpylk+EXyrBFHyLrecNSEYfdc3ROHhb//U6z8+mi1IQNRlEbQhKdWMyt+ qd3t+XryOj9RRZTrdhS5x7pTa4qMRpDH9XNaBMIYtHQ8eE8McCohj4p/InavgtI= =GooN -----END PGP SIGNATURE----- --=-XKqA/i7U/lNCuixbxF+s--