From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751319AbcGGEQu (ORCPT ); Thu, 7 Jul 2016 00:16:50 -0400 Received: from darkcity.gna.ch ([195.226.6.51]:35134 "EHLO mail.gna.ch" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750697AbcGGEQt (ORCPT ); Thu, 7 Jul 2016 00:16:49 -0400 Subject: Re: [PATCH] drm/radeon: Remove deprecated create_singlethread_workqueue To: Tejun Heo References: <20160702110350.GA3601@Karyakshetra> <20160702134614.GB17431@htj.duckdns.org> <9e69b1fd-eb93-1fee-15af-c905ee3a202f@daenzer.net> <20160705210644.GB25394@htj.duckdns.org> <936c5bae-b8e6-bf64-8be2-d27608814fac@daenzer.net> <20160706134532.GF3262@mtj.duckdns.org> Cc: Bhaktipriya Shridhar , Alex Deucher , =?UTF-8?Q?Christian_K=c3=b6nig?= , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org From: =?UTF-8?Q?Michel_D=c3=a4nzer?= Message-ID: <85449fbd-45ba-7eea-8520-d0c19b8af001@daenzer.net> Date: Thu, 7 Jul 2016 12:32:33 +0900 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.1.0 MIME-Version: 1.0 In-Reply-To: <20160706134532.GF3262@mtj.duckdns.org> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="DlISLStch7J8rS84WoFGHRquTmRmXj91o" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --DlISLStch7J8rS84WoFGHRquTmRmXj91o Content-Type: multipart/mixed; boundary="sjWTdQX2kDOdSrBirC0W9PeV5taH4dXdX" From: =?UTF-8?Q?Michel_D=c3=a4nzer?= To: Tejun Heo Cc: Bhaktipriya Shridhar , Alex Deucher , =?UTF-8?Q?Christian_K=c3=b6nig?= , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Message-ID: <85449fbd-45ba-7eea-8520-d0c19b8af001@daenzer.net> Subject: Re: [PATCH] drm/radeon: Remove deprecated create_singlethread_workqueue References: <20160702110350.GA3601@Karyakshetra> <20160702134614.GB17431@htj.duckdns.org> <9e69b1fd-eb93-1fee-15af-c905ee3a202f@daenzer.net> <20160705210644.GB25394@htj.duckdns.org> <936c5bae-b8e6-bf64-8be2-d27608814fac@daenzer.net> <20160706134532.GF3262@mtj.duckdns.org> In-Reply-To: <20160706134532.GF3262@mtj.duckdns.org> --sjWTdQX2kDOdSrBirC0W9PeV5taH4dXdX Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 06.07.2016 22:45, Tejun Heo wrote: > On Wed, Jul 06, 2016 at 12:12:52PM +0900, Michel D=C3=A4nzer wrote: >=20 >> Not being very familiar with the workqueue APIs, I'll describe how it'= s >> supposed to work from a driver POV, which will hopefully help you guys= >> decide on the most appropriate alloc_workqueue parameters. >> >> There is one flip work queue for each hardware CRTC. At most one >> radeon_flip_work_func item can be queued for any of them at any time. >> When a radeon_flip_work_func item is queued, it should be executed ASA= P >> (so WQ_HIGHPRI might be appropriate?). >=20 > Hmmm... the only time WQ_HIGHPRI should be used is when it'd otherwise > require a kthread w/ nice value at -20. Would that be the case here? > What are the consequences of the work item getting delayed? A page flip may be delayed to a later display refresh cycle. > Also, what kind of delays matter here? Is it millisec range or micro? It can be the latter in theory, but normally rather the former. --=20 Earthling Michel D=C3=A4nzer | http://www.amd= =2Ecom Libre software enthusiast | Mesa and X developer --sjWTdQX2kDOdSrBirC0W9PeV5taH4dXdX-- --DlISLStch7J8rS84WoFGHRquTmRmXj91o Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iEYEARECAAYFAld9zVEACgkQWoGvjmrbsgDrAQCfekwK1pjysczw5UFSVfhWjvWk WV8AnRSQm1M+QOBvbi1mNsmRh8eMEMs8 =O4ii -----END PGP SIGNATURE----- --DlISLStch7J8rS84WoFGHRquTmRmXj91o--