From patchwork Thu Oct 20 21:19:08 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robert Bragg X-Patchwork-Id: 9387587 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 49A60608A7 for ; Thu, 20 Oct 2016 21:20:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3D41729B8C for ; Thu, 20 Oct 2016 21:20:22 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 31F5D29C73; Thu, 20 Oct 2016 21:20:22 +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=-4.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED, T_DKIM_INVALID autolearn=unavailable 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 E6A5029B8C for ; Thu, 20 Oct 2016 21:20:21 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 89AF06EC67; Thu, 20 Oct 2016 21:19:37 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail-lf0-x243.google.com (mail-lf0-x243.google.com [IPv6:2a00:1450:4010:c07::243]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7EDE26EC48; Thu, 20 Oct 2016 21:19:24 +0000 (UTC) Received: by mail-lf0-x243.google.com with SMTP id x79so2188302lff.2; Thu, 20 Oct 2016 14:19:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=hbww5f0WymgvrSy5kQ9SE3c+LzBzW+ut1L5DlcxSJ5M=; b=hD//8vXkGZwivSWWj2JRo3zkAsOZoDShRxmGgC4vqILVAIkn5TAV177IQgM4lMuxfi jZvbKM+fN25JgL5TaiynaTtAcN0vkeFfSLYRqiWKvetlrLHry+ssQFqWY/ABDZaqV0a+ hlh0y/7ZspcUhifCXSMER3qwSxQR8VVx51fmH8uMKbbqMnhwLbotAp1DfoKGA4+K4MUp zhtSwaG5z/1/aYkQQy03bubGeeJKFLvjGGUte5At4gU2shDZIui9MtKGkKTx266LrO0b oE/wpI5rXUbt4lXN7/wbFMU6ByHCBsmin/cUe6tY1AOj3XWQqYPW4MSbiYO6HUXIYa0M 8INw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references; bh=hbww5f0WymgvrSy5kQ9SE3c+LzBzW+ut1L5DlcxSJ5M=; b=mF/WP2xi2EgwcxYgd/uCSsphnZsSzEcKqjoJUNpABf7Mxd22eM2REeMWZFj23CWStM CoT4pThUDGVW1RHYG5B/kwR0c/fhuRA/1keU0ElutvehmiE5JHkNbgmgUArCgjZgpP60 lo4+/ohotrNwa6Yx6gVZ51mOFpYJrzKHL01s+giELG3ENGEXDV3MVY/B9MZ4zVD+RnFV MC5T1kOdqhkrwfp+ok2o4eeU4n8IyXz3p2xGDuHKJZ15N1so/yxQpTG3USgoIbgSZq9H JZ/d63pDp/nqQYoSyVBJmvi6byPTxbHiN2sMuV0xglR/CH/6L8P6e+32P3DCQpXgNirf 0h3g== X-Gm-Message-State: AA6/9Rma2fN+1PmFaZMbDGqjDYXQgDCVEZZl1+JSsfFzBSET2Mq13/d+dHyBNJBySgcjMQ== X-Received: by 10.28.169.19 with SMTP id s19mr7065097wme.45.1476998362785; Thu, 20 Oct 2016 14:19:22 -0700 (PDT) Received: from sixbynine.org (cpc26-heme10-2-0-cust305.9-1.cable.virginm.net. [86.3.57.50]) by smtp.gmail.com with ESMTPSA id j1sm71283093wjl.21.2016.10.20.14.19.22 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 20 Oct 2016 14:19:22 -0700 (PDT) From: Robert Bragg To: intel-gfx@lists.freedesktop.org Subject: [PATCH v6 09/11] drm/i915: add oa_event_min_timer_exponent sysctl Date: Thu, 20 Oct 2016 22:19:08 +0100 Message-Id: <20161020211910.4723-9-robert@sixbynine.org> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20161020211910.4723-1-robert@sixbynine.org> References: <20161020211910.4723-1-robert@sixbynine.org> Cc: dri-devel@lists.freedesktop.org, Matthew Auld , Sourab Gupta , Daniel Vetter , Robert Bragg X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP The minimal sampling period is now configurable via a dev.i915.oa_min_timer_exponent sysctl parameter. Following the precedent set by perf, the default is the minimum that won't (on its own) exceed the default kernel.perf_event_max_sample_rate default of 100000 samples/s. Signed-off-by: Robert Bragg Reviewed-by: Matthew Auld --- drivers/gpu/drm/i915/i915_perf.c | 41 ++++++++++++++++++++++++++++------------ 1 file changed, 29 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c index 1d61731..4e985dd 100644 --- a/drivers/gpu/drm/i915/i915_perf.c +++ b/drivers/gpu/drm/i915/i915_perf.c @@ -82,6 +82,22 @@ static u32 i915_perf_stream_paranoid = true; #define INVALID_CTX_ID 0xffffffff +/* for sysctl proc_dointvec_minmax of i915_oa_min_timer_exponent */ +static int oa_exponent_max = OA_EXPONENT_MAX; + +/* Theoretically we can program the OA unit to sample every 160ns but don't + * allow that by default unless root... + * + * The period is derived from the exponent as: + * + * period = 80ns * 2^(exponent + 1) + * + * Referring to perf's kernel.perf_event_max_sample_rate for a precedent + * (100000 by default); with an OA exponent of 6 we get a period of 10.240 + * microseconds - just under 100000Hz + */ +static u32 i915_oa_min_timer_exponent = 6; + /* XXX: beware if future OA HW adds new report formats that the current * code assumes all reports have a power-of-two size and ~(size - 1) can * be used as a mask to align the OA tail pointer. @@ -1349,21 +1365,13 @@ static int read_properties_unlocked(struct drm_i915_private *dev_priv, return -EINVAL; } - /* NB: The exponent represents a period as follows: - * - * 80ns * 2^(period_exponent + 1) - * - * Theoretically we can program the OA unit to sample + /* Theoretically we can program the OA unit to sample * every 160ns but don't allow that by default unless * root. - * - * Referring to perf's - * kernel.perf_event_max_sample_rate for a precedent - * (100000 by default); with an OA exponent of 6 we get - * a period of 10.240 microseconds -just under 100000Hz */ - if (value < 6 && !capable(CAP_SYS_ADMIN)) { - DRM_ERROR("Sampling period too high without root privileges\n"); + if (value < i915_oa_min_timer_exponent && + !capable(CAP_SYS_ADMIN)) { + DRM_ERROR("OA timer exponent too low without root privileges\n"); return -EACCES; } @@ -1471,6 +1479,15 @@ static struct ctl_table oa_table[] = { .extra1 = &zero, .extra2 = &one, }, + { + .procname = "oa_min_timer_exponent", + .data = &i915_oa_min_timer_exponent, + .maxlen = sizeof(i915_oa_min_timer_exponent), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &oa_exponent_max, + }, {} };