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=-0.6 required=3.0 tests=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 6283FC4332D for ; Thu, 19 Mar 2020 10:34:54 +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 2809620722 for ; Thu, 19 Mar 2020 10:34:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="i7ytroA6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2809620722 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 B32F76E9FA; Thu, 19 Mar 2020 10:34:45 +0000 (UTC) Received: from mail-wr1-x444.google.com (mail-wr1-x444.google.com [IPv6:2a00:1450:4864:20::444]) by gabe.freedesktop.org (Postfix) with ESMTPS id 97B8A6E9F0 for ; Thu, 19 Mar 2020 10:34:43 +0000 (UTC) Received: by mail-wr1-x444.google.com with SMTP id f3so2145566wrw.7 for ; Thu, 19 Mar 2020 03:34:43 -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:in-reply-to; bh=+HsihkrBV/Vt2ATCPXC+nbaVsuM4g0AQNEdfwqBce2w=; b=i7ytroA6IFoY56neWMQRdmqsJF+XwgwP0QuMdAXb+b8Q67dIexlUI2biFAF1sa/cmN mtAdTS8M7LC92pRr4HjTcfkPryjW+itGJiwyqYg/+YXjRWjOdB6hL2YEEiBPiWu+ao17 Z9mjkmydrTqqMr2ZiD3kd+3XxNA5AuDs+uPPk= 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:in-reply-to; bh=+HsihkrBV/Vt2ATCPXC+nbaVsuM4g0AQNEdfwqBce2w=; b=M1frhDgubj2dm1NfeJR1BIcW1/cqp3ippKEKmRckq3oeEuMwraTetIVDcUdrMtO4ML vnRjlqDGQ653v4J4uncpmbsoQj1x5heDtWu2VhPwOt6xvbhA/yhF7T6VjZN+yOeTjcS+ b43BdkkKMTRVJuLEJYV8yhu9XnG3j+5joSyv7a5d3JpGVYzjGpMSCsa+MPPmrxqZONCk 8g+WEIdcXI2+BltYlNrfAo+PhMe8r9+loM3cwKYov+syO+/MnmzkkgxXpYnHhMhoXCln McBNR7snOV6sVuEGC1LoDQWMqhTHjcyVlG1nBJZhyfM01mL5ebEXA5jK9U24VJg058uu kQcw== X-Gm-Message-State: ANhLgQ0RZ+41Q+/dAxCHmvkPc6oAFzZ85zI+h7dPBGMMsAdzFJltpHBw VL/5B7ghFlSIK6FjZfQAjW5EzoTOcViF1wLn X-Google-Smtp-Source: ADFU+vsMVI1BEcGQKKKo+aVa8NuKFNjePiIKK/z1ToX/o3DCKebfP+Mg2xY266tS9kf2MfW9je6Bjw== X-Received: by 2002:adf:e891:: with SMTP id d17mr3387478wrm.348.1584614082081; Thu, 19 Mar 2020 03:34:42 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id h12sm1550335wml.12.2020.03.19.03.34.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Mar 2020 03:34:41 -0700 (PDT) Date: Thu, 19 Mar 2020 11:34:39 +0100 From: Daniel Vetter To: Jason Ekstrand Subject: Re: [Mesa-dev] Plumbing explicit synchronization through the Linux ecosystem Message-ID: <20200319103439.GC2363188@phenom.ffwll.local> References: <33d1749d876a83416c44671efcb37c74f87d1bd4.camel@ndufresne.ca> <20200316102034.GA30883@pendragon.ideasonboard.com> <20200316211502.GW4732@pendragon.ideasonboard.com> <74477a20fa78758dd6cf8c32d7a77d1cccf2646f.camel@ndufresne.ca> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Operating-System: Linux phenom 5.3.0-3-amd64 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: Jacob Lifshay , Daniel Vetter , xorg-devel , Maling list - DRI developers , "wayland-devel @ lists . freedesktop . org" , Laurent Pinchart , Discussion of the development of and with GStreamer , ML mesa-dev , Nicolas Dufresne , "open list:DMA BUFFER SHARING FRAMEWORK" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Tue, Mar 17, 2020 at 12:18:47PM -0500, Jason Ekstrand wrote: > On Tue, Mar 17, 2020 at 12:13 PM Jacob Lifshay wrote: > > > > One related issue with explicit sync using sync_file is that combined > > CPUs/GPUs (the CPU cores *are* the GPU cores) that do all the > > rendering in userspace (like llvmpipe but for Vulkan and with extra > > instructions for GPU tasks) but need to synchronize with other > > drivers/processes is that there should be some way to create an > > explicit fence/semaphore from userspace and later signal it. This > > seems to conflict with the requirement for a sync_file to complete in > > finite time, since the user process could be stopped or killed. > > Yeah... That's going to be a problem. The only way I could see that > working is if you created a sync_file that had a timeout associated > with it. However, then you run into the issue where you may have > corruption if stuff doesn't complete on time. Then again, you're not > really dealing with an external unit and so the latency cost of going > across the window system protocol probably isn't massively different > from the latency cost of triggering the sync_file. Maybe the answer > there is to just do everything in-order and not worry about > synchronization? vgem does that already (fences with timeout). The corruption issue is also not new, if your shaders take forever real gpus will nick your rendering with a quick reset. Iirc someone (from cros google team maybe) was even looking into making llvmpipe run on top of vgem as a real dri/drm mesa driver. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel