From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752334AbeB0HMs (ORCPT ); Tue, 27 Feb 2018 02:12:48 -0500 Received: from mail.bootlin.com ([62.4.15.54]:43830 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752314AbeB0HMn (ORCPT ); Tue, 27 Feb 2018 02:12:43 -0500 Date: Tue, 27 Feb 2018 08:12:11 +0100 From: Maxime Ripard To: Philipp Rossak Cc: linux@armlinux.org.uk, wens@csie.org, davem@davemloft.net, arnd@arndb.de, mchehab@kernel.org, clabbe.montjoie@gmail.com, rask@formelder.dk, krzk@kernel.org, sean@mess.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com Subject: Re: [RFC PATCH] ARM: configs: sunxi: Set ondemand govenor as default Message-ID: <20180227071211.4c5okbwcp5qjx4ok@flea> References: <20180217142235.28541-1-embed3d@gmail.com> <20180219081050.vvfhnbw4foved2fb@flea.lan> <15992664-76be-2584-0f8d-424eadc23925@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="2xqif3dc46ew3mkr" Content-Disposition: inline In-Reply-To: <15992664-76be-2584-0f8d-424eadc23925@gmail.com> User-Agent: NeoMutt/20180223 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --2xqif3dc46ew3mkr Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Feb 26, 2018 at 10:29:29PM +0100, Philipp Rossak wrote: >=20 >=20 > On 19.02.2018 09:10, Maxime Ripard wrote: > > On Sat, Feb 17, 2018 at 03:22:35PM +0100, Philipp Rossak wrote: > > > Right now the performance govenor is the default frequency govenor on > > > sunxi devices. This causes some general problems. > > > When the cpu is idle the cpu runs with its maximum frequency. > > > This causes a higher cpu temperature in the idle state. When the cpu = is > > > now under load the cpu gets with that higher idle temperature now fas= ter > > > to its thermal limits. > > > An other big problem of the performace govenor is the missing > > > thermal throttling. Some tests with cpuburn resulted in a system crash > > > when the soc reached its thermal limits since no thermal throttling > > > occurred. > >=20 > > This won't change anything with cpuburn. While cpuburn will be > > running, ondemand will increase the frequency of the cores to the > > maximum frequency, putting yourself in the exact same situation. > > I see here a totally different behavior on the hardware (Bananapi M2, A31= s). > First ondemand increases the cpu frequency, when the maximum temperature = is > reached, then it throttles down the cpu step by step to its minimum. This is the thermal throttling, not the cpufreq governor. Maxime --=20 Maxime Ripard, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com --2xqif3dc46ew3mkr Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEE0VqZU19dR2zEVaqr0rTAlCFNr3QFAlqVBMoACgkQ0rTAlCFN r3S6ig//Yu36CVGyfUqGk2hGDK218HKJIjUxE1fCX4CyZuYfcK5CEH88sEd+70oM mIr/JSAi5mWymOUO8CrIE5/0ajQDbjo2x/lVsZdG6GuU/MpJUK8zc5wFuGKhg9wd YZsx6foZAGRvz47fhHb4YCdQLy+qtfqlOaKL8saHI8qzwff1iiFwhX+T1ZKBD3F2 QlN7gKESCzo+N94uOIzC8mFNWtXRtmJ2vaPd5yOCDFbHl+jZs70L0n46I1/OhAl6 Th5ks5kL+G+8Zn3PYfhC2VVZzgG2nIP9FWSsz5x4npGLd3UWMekOITOrj7aQHScy 8dvlc5MqPNThZDp3YN9UUO1Ju22csKgmiw9fF8A4smGokNTYLlfdexsVf/FhZYe0 zxrszPhEdckmcj+UBvy8eh9QVVBZGrvhdrJS8o+nniS6CWdC0OkoP8DKebpFF/Se JIQ0/98lwFWhHuTxCY4d5kH01RhJlr8CZL7nk7xzt4vUCXjhSWDoe94LJIdz49eJ eBMR9pkHgV4DgqI7oe1CblmPBJXvRITMeCDsnBPlARm03nOASbzkBDC7kH2bM+90 fHDn/qy5kL0bRGn/+WjCuLJ/zwIi9XsQEbE1WowOJh4JjBcO8mSBXM7lhVOmhLw5 3TCpdwMZSI4HYsEX2AIzcTYpbbwXmmknXsi+o+NgANDZyg57pQI= =gRQ4 -----END PGP SIGNATURE----- --2xqif3dc46ew3mkr--