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=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 B608DC433EA for ; Wed, 15 Jul 2020 11:47:31 +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 8C720206E9 for ; Wed, 15 Jul 2020 11:47:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=fooishbar-org.20150623.gappssmtp.com header.i=@fooishbar-org.20150623.gappssmtp.com header.b="1z8aHdXl" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8C720206E9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=fooishbar.org 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 940D16EACA; Wed, 15 Jul 2020 11:47:29 +0000 (UTC) Received: from mail-wr1-x42e.google.com (mail-wr1-x42e.google.com [IPv6:2a00:1450:4864:20::42e]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7DB386EAC9 for ; Wed, 15 Jul 2020 11:47:27 +0000 (UTC) Received: by mail-wr1-x42e.google.com with SMTP id j4so2300497wrp.10 for ; Wed, 15 Jul 2020 04:47:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fooishbar-org.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=MxQvlm/9+opfVBprTgWPUfxZWUWeJXQ9PpRAND7jzCM=; b=1z8aHdXlmbfhFwTIBIrHT9239EMibZ4oyVwSPv5O4nXfUP1kWfvYI8IXDtyRcK+YJ8 Cbdp9hqK6M2kqxNBcmMj9TaqqgSsUrxEUwzyEIwV9KMtrnzFYMD6ae+29YYF82oj7apF 7SZfkHMToRiJ6BPEReTeDYDaULD99pIse86/A2N1tw9MzZIcglBeDxX2Fm96bDkBKVZX cmeLIgfh3JEuW663iLQksYltWGz+fG4iAf2xWfh/1ga7yAC/SR3y7RyD4Fn4Co4uclLR nylae1KrcLhOjd2t2R3Cgw7e5VCbaBQ0pYHwSWOYQI7uABvmpUBnlElWTdC3s8XRNheM saRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=MxQvlm/9+opfVBprTgWPUfxZWUWeJXQ9PpRAND7jzCM=; b=PWchFw6lhBgJZm4zJRRvzmxS1wxrsEBm28cCLybE65Hnp/JoPy9/oa3BBo/iy2aGw7 nhhGtY+xlaXk8OQTiMbEmTUmBoK0I1bt1OZE4btak3r4KTQd3LM7Ahbu+9XbDZq2+0Hf 15uz/Y3V6Tra94uQCgF5JVED/UX3ZOrGb6XyiP7Fsos17dJDprielFACkgaWKPrw7Lru /+/UDeybtpczRZX6pLZEbpKRpQOMrIOhaGrLIlwRs5xDUmAIzyhq+5cFeA2mGrzV56zX iv8aYbSQRNW4UbuUsAg4c2vRLTrZpJ+tVx/i0n51zIJJBFnhb12x1sm5zeYyMo9sEJ7Y oJ0A== X-Gm-Message-State: AOAM532FI0oROvV76aO14KPmwkXBLQc7BIzVKSNVxHOkFc4yN8DvGlY5 f0Csl8DQSg6DhzM0YCM5CL1+CedDkTcdH029wGxJ8g== X-Google-Smtp-Source: ABdhPJzjXoEXRoTapuMQ3PFPPn22ai3KyxH95lZ/LKzly3wpn43d8Tdnan9e+Xp5j6zHbU7QctKRtvYmibDINWGGaBQ= X-Received: by 2002:adf:b18d:: with SMTP id q13mr10774518wra.256.1594813646069; Wed, 15 Jul 2020 04:47:26 -0700 (PDT) MIME-Version: 1.0 References: <20200715100432.13928-1-chris@chris-wilson.co.uk> <159480926758.13728.809663901463022623@build.alporthouse.com> In-Reply-To: From: Daniel Stone Date: Wed, 15 Jul 2020 12:47:15 +0100 Message-ID: Subject: Re: [Intel-gfx] sw_sync deadlock avoidance, take 3 To: Bas Nieuwenhuizen 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: intel-gfx , ML dri-devel , Chris Wilson Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi, On Wed, 15 Jul 2020 at 12:05, Bas Nieuwenhuizen wrote: > On Wed, Jul 15, 2020 at 12:34 PM Chris Wilson wrote: > > Maybe now is the time to ask: are you using sw_sync outside of > > validation? > > Yes, this is used as part of the Android stack on Chrome OS (need to > see if ChromeOS specific, but > https://source.android.com/devices/graphics/sync#sync_timeline > suggests not) Android used to mandate it for their earlier iteration of release fences, which was an empty/future fence having no guarantee of eventual forward progress until someone committed work later on. For example, when you committed a buffer to SF, it would give you an empty 'release fence' for that buffer which would only be tied to work to signal it when you committed your _next_ buffer, which might never happen. They removed that because a) future fences were a bad idea, and b) it was only ever useful if you assumed strictly FIFO/round-robin return order which wasn't always true. So now it's been watered down to 'use this if you don't have a hardware timeline', but why don't we work with Android people to get that removed entirely? Cheers, Daniel _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel