From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Airlie Subject: Re: [PATCH] Mapping snooped user pages into the GTT Date: Sat, 8 Jan 2011 05:37:18 +1000 Message-ID: References: <1294416456-5410-1-git-send-email-chris@chris-wilson.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1294416456-5410-1-git-send-email-chris@chris-wilson.co.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: Chris Wilson Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org On Sat, Jan 8, 2011 at 2:07 AM, Chris Wilson wrote: > I've been looking at how we can improve upload/download performance on our > UMA gfx. One under-used aspect of the IGP is its ability to blit between > snooped-and-unsnooped memory i.e. from normal ram into the GTT. Only the > BLT has this ability, almost all other functions of the GPU most be from > unsnooped memory. SNB introduces its own cache handling that we need to > exploit further, however the BLT remains and is orders of magnitude faster > for read back than an UC read by the CPU... You might want to test this on a 945G era machine, I think I tried to get this working back in the TTM days, I got a lot of crashes and pain and suffering. But I might have had bad ops happening occasionally or something. Dave.