From mboxrd@z Thu Jan  1 00:00:00 1970
From: Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [PATCH 4/4] drm/i915: Use the real cpu max
 frequency for ring scaling
Date: Tue, 8 Oct 2013 08:14:03 +0200
Message-ID: <20131008061353.GA3794@phenom.ffwll.local>
References: <1381176948-2754-1-git-send-email-rodrigo.vivi@gmail.com>
	<1381176948-2754-5-git-send-email-rodrigo.vivi@gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org>
Received: from mail-ea0-f182.google.com (mail-ea0-f182.google.com
	[209.85.215.182])
	by gabe.freedesktop.org (Postfix) with ESMTP id B5BD9E6824
	for <intel-gfx@lists.freedesktop.org>;
	Mon,  7 Oct 2013 23:13:48 -0700 (PDT)
Received: by mail-ea0-f182.google.com with SMTP id o10so3754655eaj.13
	for <intel-gfx@lists.freedesktop.org>;
	Mon, 07 Oct 2013 23:13:47 -0700 (PDT)
Content-Disposition: inline
In-Reply-To: <1381176948-2754-5-git-send-email-rodrigo.vivi@gmail.com>
List-Unsubscribe: <http://lists.freedesktop.org/mailman/options/intel-gfx>,
	<mailto:intel-gfx-request@lists.freedesktop.org?subject=unsubscribe>
List-Archive: <http://lists.freedesktop.org/archives/intel-gfx>
List-Post: <mailto:intel-gfx@lists.freedesktop.org>
List-Help: <mailto:intel-gfx-request@lists.freedesktop.org?subject=help>
List-Subscribe: <http://lists.freedesktop.org/mailman/listinfo/intel-gfx>,
	<mailto:intel-gfx-request@lists.freedesktop.org?subject=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: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Cc: intel-gfx@lists.freedesktop.org, Ben Widawsky <ben@bwidawsk.net>, Ben Widawsky <benjamin.widawsky@intel.com>
List-Id: intel-gfx@lists.freedesktop.org

On Mon, Oct 07, 2013 at 05:15:48PM -0300, Rodrigo Vivi wrote:
> From: Ben Widawsky <benjamin.widawsky@intel.com>
> 
> The policy's max frequency is not equal to the CPU's max frequency. The
> ring frequency is derived from the CPU frequency, and not the policy
> frequency.
> 
> One example of how this may differ through sysfs. If the sysfs max
> frequency is modified, that will be used for the max ring frequency
> calculation.
> (/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq). As far as I
> know, no current governor uses anything but max as the default, but in
> theory, they could. Similarly distributions might set policy as part of
> their init process.
> 
> It's ideal to use the real frequency because when we're currently scaled
> up on the GPU. In this case we likely want to race to idle, and using a
> less than max ring frequency is non-optimal for this situation.
> 
> AFAIK, this patch should have no impact on a majority of people.
> 
> This behavior hasn't been changed since it was first introduced:
> commit 23b2f8bb92feb83127679c53633def32d3108e70
> Author: Jesse Barnes <jbarnes@virtuousgeek.org>
> Date:   Tue Jun 28 13:04:16 2011 -0700
> 
>     drm/i915: load a ring frequency scaling table v3
> 
> CC: Jesse Barnes <jbarnes@virtuousgeek.org>
> Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>

Queued for -next, thanks for the patch.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch