From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: linux-rt-users-owner@vger.kernel.org Received: from mail.klingt.org ([86.59.21.178]:60404 "EHLO klingt.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726343AbeHULSm (ORCPT ); Tue, 21 Aug 2018 07:18:42 -0400 References: <0ac9fabc-c316-2a59-c3dd-c7b4e4f93209@bristot.me> <20180817095106.GB27071@localhost.localdomain> <20180817102810.GC27071@localhost.localdomain> <513fd544-bc51-7ea6-8b94-983d28922a66@klingt.org> <20180820085420.GB8866@localhost.localdomain> <0a8f899a-589d-a84b-dadb-50def9c0b4c3@santannapisa.it> From: Tim Blechmann Subject: Re: SCHED_DEADLINE as user Message-ID: Date: Tue, 21 Aug 2018 15:59:16 +0800 MIME-Version: 1.0 In-Reply-To: <0a8f899a-589d-a84b-dadb-50def9c0b4c3@santannapisa.it> Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="sira6I2NzXRdCyRhGRuNoEXry6aFidzLL" Sender: linux-rt-users-owner@vger.kernel.org List-ID: To: Tommaso Cucinotta , Juri Lelli Cc: Daniel Bristot de Oliveira , linux-rt-users@vger.kernel.org, Luca Abeni , Alessio Balsini This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --sira6I2NzXRdCyRhGRuNoEXry6aFidzLL Content-Type: multipart/mixed; boundary="gdInwU4YRS3tl6zFENUF7DbkXbKDPayh3"; protected-headers="v1" From: Tim Blechmann To: Tommaso Cucinotta , Juri Lelli Cc: Daniel Bristot de Oliveira , linux-rt-users@vger.kernel.org, Luca Abeni , Alessio Balsini Message-ID: Subject: Re: SCHED_DEADLINE as user References: <0ac9fabc-c316-2a59-c3dd-c7b4e4f93209@bristot.me> <20180817095106.GB27071@localhost.localdomain> <20180817102810.GC27071@localhost.localdomain> <513fd544-bc51-7ea6-8b94-983d28922a66@klingt.org> <20180820085420.GB8866@localhost.localdomain> <0a8f899a-589d-a84b-dadb-50def9c0b4c3@santannapisa.it> In-Reply-To: <0a8f899a-589d-a84b-dadb-50def9c0b4c3@santannapisa.it> --gdInwU4YRS3tl6zFENUF7DbkXbKDPayh3 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable >> alsa is basically driven by the hardware, which delivers/requests data= >> every ~1.3ms. >=20 > this is exactly the use-case we considered in that old paper back in LA= C > 2011, and let me just add that there is more experimentation and detail= s > and results in Giacomo's MSc thesis: >=20 > =C2=A0 https://retis.sssup.it/?q=3Dnode/77 >=20 > FYI, we restarted activities on this use-case just recently, considerin= g > a couple of further dimensions: >=20 > 1) support for heterogeneous platforms with the aim of achieving a soun= d > support for Arm big.LITTLE on Android, and apply it to the Android vide= o > & audio processing pipelines; >=20 > 2) proper consideration of power switching capabilities of the platform= > (assuming the user would block the CPU frequency to its maximum is not > really multimedia-friendly); >=20 > 3) support for multi-threaded processing workflows on multi-cores, as > typically needed by (high-performance) audio applications, either with = a > single multi-threaded audio processing client, or, e.g., with JACK, wit= h > a DAG of computations that can take advantage of underlying multi-core > processing. >=20 > In this context, we've been playing also with the hierarchical extensio= n > to SCHED_DEADLINE we sent last year on LKML >=20 > =C2=A0 https://lkml.org/lkml/2017/3/31/658 >=20 > I hope we can share some good write-up & experimental results pretty > soon about some of the above... very interesting! thanks for the links ... > I'm not sure I'm getting this: AFAIU, from this viewpoint, what you > could get > with DEADLINE, is very similar to what you can get already with RT > throttling > on RT (RR/FIFO), setting up properly CPU cgroups & limits. Why do you t= hink > DEADLINE would allow you to avoid a watchdog thread, that you need with= > RT instead ? interesting, wasn't aware of rt throttling ... (haven't done much linux audio developments for almost 10 years). will give it another read ... cheers, tim --gdInwU4YRS3tl6zFENUF7DbkXbKDPayh3-- --sira6I2NzXRdCyRhGRuNoEXry6aFidzLL Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Comment: GPGTools - http://gpgtools.org iQIcBAEBCgAGBQJbe8ZVAAoJEAIkvWiom07DWVQP/j0iMyzdHJNHLmHfOLxBSVUH ttcu+A7Dz5tO6n80ux/xOLnbdcmLhU+EJJIx6Ipc6JvOvODr1bT2xCoqYPk1SW9Z 2SFoWGBAm1WGtlSAYh5OLmVD9SX4rIJVs6VCHpsKmFoYT5xRlPVayV0VWOJXag7y dpH+GVzlaIwOqz7DBeRGI683EddeEviKGRsYPOvD/hnvU5GoOe1z844sw6uITw8z BZxnKz60Iquf2DUXQH1DSA0xCOLLAchDxxs16wjY5CN2/dSaTiJph0OaD+ivntCZ n3PmbszfdJ28c1KiNd8aNZEwD9v2pnxHIJpHHcucvxsrsc6B2yt5Rf3zRviQlHy+ oReByg48BX6YbQkqeOobJGXy4gbVWQHBBn/LI+c2vUdEOTNusZV4TPeYbEuloQuX /YyQ5+LioxrWQofD5KYiNsKFBMe0CCJf+ypbjmRuvVKr1jIyXJi6ph4GM4GBFiJF ptjbjm95tJisNdTWoEs7KH90PWTjfE/QIfa75eOOHMkOPyEuE+TuDaf4EtAuPhZj SnnuVdsR0uyMar2TRRI7OIv883rVcxaoxtGGPn8cmr5pR+KPAdvYgRR0tl3vtyuK ewAmtYCki8nC/xlpQKfi+uJUGbhRqeXuuXeGZIvHlQxZel2LvBAck09g23MM4yjf DiLocNVSoN0T4I0z/218 =o7bi -----END PGP SIGNATURE----- --sira6I2NzXRdCyRhGRuNoEXry6aFidzLL--