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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 555ADC433EF for ; Wed, 1 Jun 2022 21:25:21 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9728F10FBEB; Wed, 1 Jun 2022 21:25:20 +0000 (UTC) Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by gabe.freedesktop.org (Postfix) with ESMTPS id C501710F74A; Wed, 1 Jun 2022 21:25:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1654118718; x=1685654718; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=NcLBO901OtRF8vqUzbCUOSaO4TqbKWFE+hNLqU+5gcY=; b=Ta0Wilr+JNBOnbUDHoaOy2+9Muck+zUZgZEKwON/AgB3AG27n3g+PDKm xxW8/xG5Y0cd4jzPQbLh3HZkLGnfp+xVasJ6uZmduWnWjmWz1U4lIYT0G gxxnG8zQtCqLNJQ0qz+n44VcvkTHbv4oURJ2vWvu3K3BMn7hju6zVNz+t LpngzxobMxk5jh0gRifN4oLksNJtCngfMZS5ZkQHvdb4CKeOpLT4/JPa9 xVDOss/vs0shgTDinuh7QDJFUuZKqBzM5brrbVJVLuvQzbYd4P5GP9RYf a8LvzvbPhdOMzlmy1w7GDjRTwplI1tBbjSxJFItsxgfWsoYyQRAoCL2Dj w==; X-IronPort-AV: E=McAfee;i="6400,9594,10365"; a="255604696" X-IronPort-AV: E=Sophos;i="5.91,269,1647327600"; d="scan'208";a="255604696" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jun 2022 14:25:18 -0700 X-IronPort-AV: E=Sophos;i="5.91,269,1647327600"; d="scan'208";a="756640880" Received: from jons-linux-dev-box.fm.intel.com (HELO jons-linux-dev-box) ([10.1.27.20]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jun 2022 14:25:12 -0700 Date: Wed, 1 Jun 2022 14:18:49 -0700 From: Matthew Brost To: Lionel Landwerlin Message-ID: <20220601211849.GA30517@jons-linux-dev-box> References: <20220517183212.20274-1-niranjana.vishwanathapura@intel.com> <20220517183212.20274-2-niranjana.vishwanathapura@intel.com> <43746609-4f60-f347-5934-6680516297dd@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43746609-4f60-f347-5934-6680516297dd@intel.com> User-Agent: Mutt/1.9.4 (2018-02-28) Subject: Re: [Intel-gfx] [RFC v3 1/3] drm/doc/rfc: VM_BIND feature design document X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, thomas.hellstrom@intel.com, chris.p.wilson@intel.com, daniel.vetter@intel.com, christian.koenig@amd.com Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Wed, Jun 01, 2022 at 05:25:49PM +0300, Lionel Landwerlin wrote: > On 17/05/2022 21:32, Niranjana Vishwanathapura wrote: > > +VM_BIND/UNBIND ioctl will immediately start binding/unbinding the mapping in an > > +async worker. The binding and unbinding will work like a special GPU engine. > > +The binding and unbinding operations are serialized and will wait on specified > > +input fences before the operation and will signal the output fences upon the > > +completion of the operation. Due to serialization, completion of an operation > > +will also indicate that all previous operations are also complete. > > I guess we should avoid saying "will immediately start binding/unbinding" if > there are fences involved. > > And the fact that it's happening in an async worker seem to imply it's not > immediate. > > > I have a question on the behavior of the bind operation when no input fence > is provided. Let say I do : > > VM_BIND (out_fence=fence1) > > VM_BIND (out_fence=fence2) > > VM_BIND (out_fence=fence3) > > > In what order are the fences going to be signaled? > > In the order of VM_BIND ioctls? Or out of order? > > Because you wrote "serialized I assume it's : in order > > > One thing I didn't realize is that because we only get one "VM_BIND" engine, > there is a disconnect from the Vulkan specification. > > In Vulkan VM_BIND operations are serialized but per engine. > > So you could have something like this : > > VM_BIND (engine=rcs0, in_fence=fence1, out_fence=fence2) > > VM_BIND (engine=ccs0, in_fence=fence3, out_fence=fence4) > Question - let's say this done after the above operations: EXEC (engine=ccs0, in_fence=NULL, out_fence=NULL) Is the exec ordered with respected to bind (i.e. would fence3 & 4 be signaled before the exec starts)? Matt > > fence1 is not signaled > > fence3 is signaled > > So the second VM_BIND will proceed before the first VM_BIND. > > > I guess we can deal with that scenario in userspace by doing the wait > ourselves in one thread per engines. > > But then it makes the VM_BIND input fences useless. > > > Daniel : what do you think? Should be rework this or just deal with wait > fences in userspace? > > > Sorry I noticed this late. > > > -Lionel > >