From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Sun, Daisy" Subject: Re: [PATCH v2] drm/i915/bdw: BDW Software Turbo Date: Thu, 10 Jul 2014 11:42:59 -0700 Message-ID: <53BEDEB3.2000003@intel.com> References: <1404954048-15265-1-git-send-email-daisy.sun@intel.com> <20140710083238.GK8986@nuc-i3427.alporthouse.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by gabe.freedesktop.org (Postfix) with ESMTP id C0BCA6E025 for ; Thu, 10 Jul 2014 11:43:34 -0700 (PDT) In-Reply-To: <20140710083238.GK8986@nuc-i3427.alporthouse.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Chris Wilson , intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org GT is not going to run at a single frequency all the time actually. It starts from a single frequency, and then will dynamically adjust according to the GT utilization, either go up or down. From this perspective, SW turbo function the same as the HW turbo. For the algorithm, we did go over the design forum before implementation. What kind of improvement is expected? Please let me know if any important case is not taken into account. Thanks. - Daisy On 7/10/2014 1:32 AM, Chris Wilson wrote: > On Wed, Jul 09, 2014 at 06:00:48PM -0700, Daisy Sun wrote: >> BDW supports GT C0 residency reporting in constant time unit. Driver calculates >> GT utilization based on C0 residency and adjusts RP frequency up/down >> accordingly. > This explanation is a bit thin on the ground for why you want to run > permanently at a single GPU frequency. And the algorithm looks primitive > at best. > -Chris >