From mboxrd@z Thu Jan 1 00:00:00 1970 From: Knut Petersen Subject: Performance regression, please revert commit 441ef916ae6569c88b3d6abaf7fea4d69be49d76 Date: Sun, 13 Jan 2013 11:09:38 +0100 Message-ID: <50F287E2.9030709@t-online.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mailout03.t-online.de (mailout03.t-online.de [194.25.134.81]) by gabe.freedesktop.org (Postfix) with ESMTP id 31DAEE60DB for ; Sun, 13 Jan 2013 02:25:24 -0800 (PST) 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 List-Id: intel-gfx@lists.freedesktop.org There is a massive performance regression on i915GM hardware, opening/closing/redrawing looks as if it is done in slow motion. I bisected the problem to: commit 441ef916ae6569c88b3d6abaf7fea4d69be49d76 Author: Chris Wilson Date: Thu Jan 10 19:14:21 2013 +0000 intel: Throttle harder Filling the rings is a very unpleasant user experience, so cap the number of batches we allow to be inflight at any one time. Interestingly, as also found with SNA, throttling can improve performance by reducing RSS. However, typically throughput is improved (at the expense of latency) by oversubscribing work to the GPU and a 10-20% slowdown is commonplace for cairo-traces. Notably, x11perf is less affected and in particular application level benchmarks show no change. Note that this exposes another bug in libdrm-intel 2.4.40 on gen2/3. Signed-off-by: Chris Wilson Please revert 441ef (or limit the new code to hardware that benefits from it) cu, Knut