From patchwork Thu May 3 06:37:14 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 10377173 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 42883603B4 for ; Thu, 3 May 2018 06:39:18 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 33A3B251F9 for ; Thu, 3 May 2018 06:39:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 28AF028E2B; Thu, 3 May 2018 06:39:18 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id D22F7251F9 for ; Thu, 3 May 2018 06:39:17 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6BB566E6D5; Thu, 3 May 2018 06:39:11 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7470D6E6C6 for ; Thu, 3 May 2018 06:39:08 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from haswell.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 11578266-1500050 for multiple; Thu, 03 May 2018 07:39:02 +0100 Received: by haswell.alporthouse.com (sSMTP sendmail emulation); Thu, 03 May 2018 07:39:01 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Thu, 3 May 2018 07:37:14 +0100 Message-Id: <20180503063757.22238-28-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180503063757.22238-1-chris@chris-wilson.co.uk> References: <20180503063757.22238-1-chris@chris-wilson.co.uk> X-Originating-IP: 78.156.65.138 X-Country: code=GB country="United Kingdom" ip=78.156.65.138 Subject: [Intel-gfx] [PATCH 28/71] drm/i915: Reduce RPS update frequency on Valleyview/Cherryview X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP Valleyview and Cherryview update the GPU frequency via the punit, which is very expensive as we have to ensure the cores do not sleep during the comms. If we perform frequent RPS evaluations, the frequent punit requests cause measurable system overhead for little benefit, so increase the evaluation intervals to reduce the number of times we try and change frequency. Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/intel_pm.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 53a719a84f91..5f59cb81d489 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -6342,6 +6342,19 @@ static void gen6_set_rps_thresholds(struct drm_i915_private *dev_priv, u8 val) break; } + if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) { + /* + * Baytrail and Braswell control the gpu frequency via the + * punit, which is very slow and expensive to communicate with, + * as we synchronously force the package to C0. If we try and + * update the gpufreq too often we cause measurable system + * load for little benefit (effectively stealing CPU time for + * the GPU, negatively impacting overall throughput). + */ + ei_up <<= 2; + ei_down <<= 2; + } + /* When byt can survive without system hang with dynamic * sw freq adjustments, this restriction can be lifted. */