From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 58FE8EB64DA for ; Tue, 4 Jul 2023 09:25:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231487AbjGDJZl (ORCPT ); Tue, 4 Jul 2023 05:25:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48378 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230273AbjGDJZk (ORCPT ); Tue, 4 Jul 2023 05:25:40 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 82006C9 for ; Tue, 4 Jul 2023 02:25:39 -0700 (PDT) Date: Tue, 4 Jul 2023 11:25:32 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1688462736; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=qPnlV1qPV+FX8QsFJRDWzuCP7fOxJePUcEoo+JgtoPs=; b=lp21xsRQj2oKCzfdJmcUc1FSy0uY8z3gLG3hShsOf0roe3BWiQj/kve1KTUWYkIrpYCcYK QwOQ89UXgt50/CmoD6I8JHKvE2nbhohfT5PniziHjyf2HhpZb12YDkIOApgfIMiODJYutR 20dJ2ps8Rt8658KiH/XcjtQGDyJeg1SIMN3hgCaBUWc07HChNPXOwunr+9jUVqsYCzN/sj d9cmKy6iS6DL5z3zRv07L34FnFS5n0Vzk1qOTIZBrvlNguBZkMsY/3LQOY6LdrumnhZT6O 9AUsSZh5n3a91hknIVbLJB8ARleXzGmjU+up3QXv4uAvSkJzJRfsEGWQKyPxYA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1688462736; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=qPnlV1qPV+FX8QsFJRDWzuCP7fOxJePUcEoo+JgtoPs=; b=aMWtnbWJe0xZRfzZFBVo+Yz/KKBAFcoweeZhIKJWwU+3Hj+G7uK8qfv6gktPaluvIOvK90 ZXKoVqzOg9RFcUBQ== From: Sebastian Andrzej Siewior To: Tvrtko Ursulin Cc: Paul Gortmaker , Chris Wilson , Daniele Ceraolo Spurio , linux-rt-users@vger.kernel.org, intel-gfx@lists.freedesktop.org, Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Thomas Gleixner Subject: Re: [RFC] tentative fix for drm/i915/gt regression on preempt-rt Message-ID: <20230704092532.k-Fi14oC@linutronix.de> References: <20230630130949.coN0sVU4@linutronix.de> <5af9b5cb-2342-8de3-07f2-86f2be6201eb@linux.intel.com> <20230703161256.21Qmrm9d@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org On 2023-07-04 09:02:07 [+0100], Tvrtko Ursulin wrote: > Lets make it a two patch series and then see. First patch to see if we can > really get away without the top level preempt_disable, and then second patch > to see if we can get away with preemptible short sleeps too. oki. > I guess on RT the top priority is consistent scheduling latency and not so > much potential UI latency in some edge cases? Saying that because if waiting I would says, yes. If you do RT and you provide some kind of GUI then you prefer to meet your deadlines for your RT load over some UI latency. > on the hw reset is made preemptible, _in theory_ it can prolong the reset > completion (as observed by i915), and so result in more UI glitching than it > normally would. Could be a theoretical point only because it requires both > CPU over-subscribe and GPU hangs. It could also easily be that the reset > path is only one path, and not so interesting one even, which can cause this > on RT. I see. > Regards, > > Tvrtko Sebastian