From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH 4/9] drm/i915: don't update GEN6_PMIMR when it's not needed Date: Tue, 20 Aug 2013 16:18:37 +0200 Message-ID: <20130820141837.GS776@phenom.ffwll.local> References: <1375826239-3060-1-git-send-email-przanoni@gmail.com> <1375826239-3060-5-git-send-email-przanoni@gmail.com> <20130807003508.GA10740@cantiga.alporthouse.com> <20130807141451.GA16248@cantiga.alporthouse.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ee0-f48.google.com (mail-ee0-f48.google.com [74.125.83.48]) by gabe.freedesktop.org (Postfix) with ESMTP id 852ABE625C for ; Tue, 20 Aug 2013 07:18:26 -0700 (PDT) Received: by mail-ee0-f48.google.com with SMTP id l10so234798eei.35 for ; Tue, 20 Aug 2013 07:18:25 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20130807141451.GA16248@cantiga.alporthouse.com> 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 , Paulo Zanoni , intel-gfx@lists.freedesktop.org, Paulo Zanoni List-Id: intel-gfx@lists.freedesktop.org On Wed, Aug 07, 2013 at 03:14:51PM +0100, Chris Wilson wrote: > On Wed, Aug 07, 2013 at 10:34:11AM -0300, Paulo Zanoni wrote: > > 2013/8/6 Chris Wilson : > > > On Tue, Aug 06, 2013 at 06:57:14PM -0300, Paulo Zanoni wrote: > > >> From: Paulo Zanoni > > >> > > >> I did some brief tests and the "new_val = pmimr" condition usually > > >> happens a few times after exiting games. > > >> > > >> Signed-off-by: Paulo Zanoni > > > > > > I'm not sure of the value of this patch by itself. It did make me wonder > > > what you were micro-optimising, and then I saw patch 5 and it made more > > > sense. > > > > Patches 4 and 5 are just micro optimizations and shouldn't be needed > > for the PC8+, but I thought they would be useful. If you think they're > > not worth it, we can discard them. I was trying to make the code > > similar to the other IMR-changing functions. > > Combined together, I think the micro-optimisation makes sense and would > say it was less of a micro-optimisation than a consistent design to use > the bookkeeping instead of touching registers. Just on its own this > patch caused me to do a double-take and question what your motivation > was. I've added a small note to the commit message to (hopefully) capture this. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch