From patchwork Mon Aug 15 14:41:26 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robert Bragg X-Patchwork-Id: 9281163 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 286C8607FD for ; Mon, 15 Aug 2016 14:41:55 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 136FD28D06 for ; Mon, 15 Aug 2016 14:41:55 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 082EC28D0D; Mon, 15 Aug 2016 14:41:55 +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=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 B2EFB28D06 for ; Mon, 15 Aug 2016 14:41:54 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id BD6DE6E560; Mon, 15 Aug 2016 14:41:51 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail-wm0-x242.google.com (mail-wm0-x242.google.com [IPv6:2a00:1450:400c:c09::242]) by gabe.freedesktop.org (Postfix) with ESMTPS id BB2B86E560; Mon, 15 Aug 2016 14:41:50 +0000 (UTC) Received: by mail-wm0-x242.google.com with SMTP id o80so11504040wme.0; Mon, 15 Aug 2016 07:41:50 -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=cX0pMFfoiBMls9Y/8HAiVGqOp0fryqS1gh5mWD6cROA=; b=WFL6gKJXG1+KAg8ONMpjZT58ui/mEqQtVRLp5Z6PksTGPX/LCTo43qICOGM3drbWNG l0yADCt8WwTxt1optU0kP+Kd6Qa5FaVPNyYBhQSStgWoV2Rw7rdhmlNHihL4fCvyLRmo M7Q4/AJPzY/8FDX1ZkHA83WUmW51qRSZOzTd3IjMBbCDDvLOthqc39QGROFUJOf7JG+v /Mo2xaENs0+CQMUbIeo6cyPbhgj+kcxZYlGsAkZ5Uok4p2O7AqG2YQBfu4TYUmL2kaok WHoUdiA2PPvZd62E2hGGztExjh9OrE+vYBp9/gjAll9t+BBUIfKOTHF/6FUXwx+X14k/ X97g== 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=cX0pMFfoiBMls9Y/8HAiVGqOp0fryqS1gh5mWD6cROA=; b=fU00DL2jmtIyEXNz7pzAWgWswBi/bSwtegSGu4EDUppBisPm2OfRMsAOLFZZdX0no3 QUZzEI7f7ZhezCWXVDKTeOrZsimYj2TzKy7sMZnjmlsUPfakQIvACjoEr8BOQQxe8Gfh RzBJx5XclltCRKPWp3qMjLVBvtEcUvu2gZ0ow78mZrlwCRtlZgmGsfdwMqWsljLB59SJ 5BqSeWYvpflYVJeNlmWjUfZxArp0CKqBmSZgHr+381kzmRMwZXylmhxMQEXrOIUi9rx1 YVMdsQRojqBGSL7ephw+7wuqi+OE8JNHYh5WTmG8pPgyhkTMsoaFRC/CpDxDXVFfnNQK ryUg== X-Gm-Message-State: AEkoouute4OVbTcBX2dQVGHI9N5NYXIQ/rq3K9adOxR39fXn+VkEqBsdF+0pvvdcjr6a8g== X-Received: by 10.194.186.166 with SMTP id fl6mr31462959wjc.44.1471272109031; Mon, 15 Aug 2016 07:41:49 -0700 (PDT) Received: from sixbynine.org ([192.198.151.62]) by smtp.gmail.com with ESMTPSA id g1sm12689966wjy.5.2016.08.15.07.41.48 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 15 Aug 2016 07:41:48 -0700 (PDT) From: Robert Bragg To: intel-gfx@lists.freedesktop.org Subject: [PATCH v3 09/11] drm/i915: add oa_event_min_timer_exponent sysctl Date: Mon, 15 Aug 2016 15:41:26 +0100 Message-Id: <20160815144128.7847-10-robert@sixbynine.org> X-Mailer: git-send-email 2.9.2 In-Reply-To: <20160815144128.7847-1-robert@sixbynine.org> References: <20160815144128.7847-1-robert@sixbynine.org> Cc: dri-devel@lists.freedesktop.org, 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 --- drivers/gpu/drm/i915/i915_perf.c | 42 ++++++++++++++++++++++++++++------------ 1 file changed, 30 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c index c9e7104..18cb651 100644 --- a/drivers/gpu/drm/i915/i915_perf.c +++ b/drivers/gpu/drm/i915/i915_perf.c @@ -74,6 +74,23 @@ static u32 i915_perf_stream_paranoid = true; */ #define OA_EXPONENT_MAX 31 +/* for sysctl proc_dointvec_minmax of i915_oa_min_timer_exponent */ +static int zero; +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. @@ -1266,21 +1283,13 @@ 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; } @@ -1342,6 +1351,15 @@ static struct ctl_table oa_table[] = { .mode = 0644, .proc_handler = proc_dointvec, }, + { + .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, + }, {} };