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 X-Spam-Level: X-Spam-Status: No, score=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4A663C47083 for ; Wed, 2 Jun 2021 18:48:25 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1377661360 for ; Wed, 2 Jun 2021 18:48:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1377661360 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 795E889191; Wed, 2 Jun 2021 18:48:20 +0000 (UTC) Received: from mail-wr1-x435.google.com (mail-wr1-x435.google.com [IPv6:2a00:1450:4864:20::435]) by gabe.freedesktop.org (Postfix) with ESMTPS id 168AB6EDF0 for ; Wed, 2 Jun 2021 18:48:19 +0000 (UTC) Received: by mail-wr1-x435.google.com with SMTP id h8so3287867wrz.8 for ; Wed, 02 Jun 2021 11:48:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=F6gQcd+qTlqkWsY+lbSteha4KL5f4gwPP7np80DTFoM=; b=a2AMHAHVEgwldzVWOsLdVU8+7pWgoeA5TfGfYuxBH6gnFq21+FBx5zpp1pyTxd1hjW gHApIJ6698FmTld1K/VddKsBfoM34bbHUnH+Os874ltp/TiDqp77g71pL4D3M5gLESMf ym+CgwDwSk7NjOQhEaw2s64oH/8+XfsWIaq4k= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=F6gQcd+qTlqkWsY+lbSteha4KL5f4gwPP7np80DTFoM=; b=LzY7VwWfLpV00s+f7TDbsHO1ifka1/lbZ4+jlxQ5Xf1lrwn2Kxpew7G/A9tdSSapLR bR9mv8xpRzrUmGGjDw3zqop6WNUxjnvtvZhcTqmkt0BRvUbz1sIYnsAKqLMSAkzmL5Z2 jDQhxIcTkRenKvSAkzdjMLQZRJWVS1jheGrQU3z8NUBQIBweVIrARXR95stt4BfP3OUZ lTDqAh0IIns8seY8Px4cIplseFnYugkskNI+lxa1TA6kRIQ24a/PPNABOo6IQ33Nk18t iGwJf646NF7vngwTQrcLA3wiEUVPKSarGm0Eiq9fCOGqRooMEKa1DiJ/bgyL4dF+sldn Tk8g== X-Gm-Message-State: AOAM531R5bIerk3wxkpaG9iMA1/SgdQPetzjivewPpIeuB5mAjsZS5p5 v9FW5oNoQQ2N5tDofrNJ1jQTHFAKKIT/sg== X-Google-Smtp-Source: ABdhPJw3gNEdfSaLqE/zhUnrAKIkqn6LMsfMyTRpzEOjRHdOTEIyyyqM2ebNHNDmzJnMNixHHj5/QQ== X-Received: by 2002:a5d:64a3:: with SMTP id m3mr34375943wrp.172.1622659697809; Wed, 02 Jun 2021 11:48:17 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id s1sm3562332wmj.8.2021.06.02.11.48.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Jun 2021 11:48:17 -0700 (PDT) Date: Wed, 2 Jun 2021 20:48:15 +0200 From: Daniel Vetter To: Marek =?utf-8?B?T2zFocOhaw==?= Subject: Re: [Mesa-dev] Linux Graphics Next: Userspace submission update Message-ID: References: <327e4008-b29f-f5b7-bb30-532fa52c797f@gmail.com> <7f19e3c7-b6b2-5200-95eb-3fed8d22a6b3@daenzer.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Operating-System: Linux phenom 5.10.32scarlett+ X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jason Ekstrand , Christian =?iso-8859-1?Q?K=F6nig?= , Michel =?iso-8859-1?Q?D=E4nzer?= , dri-devel , ML Mesa-dev Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Wed, Jun 02, 2021 at 05:38:51AM -0400, Marek Olšák wrote: > On Wed, Jun 2, 2021 at 5:34 AM Marek Olšák wrote: > > > Yes, we can't break anything because we don't want to complicate things > > for us. It's pretty much all NAK'd already. We are trying to gather more > > knowledge and then make better decisions. > > > > The idea we are considering is that we'll expose memory-based sync objects > > to userspace for read only, and the kernel or hw will strictly control the > > memory writes to those sync objects. The hole in that idea is that > > userspace can decide not to signal a job, so even if userspace can't > > overwrite memory-based sync object states arbitrarily, it can still decide > > not to signal them, and then a future fence is born. > > > > This would actually be treated as a GPU hang caused by that context, so it > should be fine. This is practically what I proposed already, except your not doing it with dma_fence. And on the memory fence side this also doesn't actually give what you want for that compute model. This seems like a bit a worst of both worlds approach to me? Tons of work in the kernel to hide these not-dma_fence-but-almost, and still pain to actually drive the hardware like it should be for compute or direct display. Also maybe I've missed it, but I didn't see any replies to my suggestion how to fake the entire dma_fence stuff on top of new hw. Would be interesting to know what doesn't work there instead of amd folks going of into internal again and then coming back with another rfc from out of nowhere :-) -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch