From patchwork Thu Apr 29 00:34:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Umesh Nerlige Ramappa X-Patchwork-Id: 12230283 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4C52C433B4 for ; Thu, 29 Apr 2021 00:34:19 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 71A94613F8 for ; Thu, 29 Apr 2021 00:34:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 71A94613F8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 5FAB06ECD7; Thu, 29 Apr 2021 00:34:14 +0000 (UTC) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by gabe.freedesktop.org (Postfix) with ESMTPS id E562B6ECD1; Thu, 29 Apr 2021 00:34:11 +0000 (UTC) IronPort-SDR: BpEe6yMLOP5jFrDhgokp8cUY924GQiLPvGOBLn+PXT7jN3/PIzC3BhA/Gbgp4NLpijScpFiLmD BITpXro1qleg== X-IronPort-AV: E=McAfee;i="6200,9189,9968"; a="196444288" X-IronPort-AV: E=Sophos;i="5.82,258,1613462400"; d="scan'208";a="196444288" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Apr 2021 17:34:11 -0700 IronPort-SDR: ER2DOn79LmLNM/sLST0Sm9MfOuB0AkW8BX8PIfaAvPVraazZs0YYohzmdvpVlN6cy2Fu3PPH+C CwBHvAQtCBmg== X-IronPort-AV: E=Sophos;i="5.82,258,1613462400"; d="scan'208";a="466135262" Received: from orsosgc001.ra.intel.com ([10.23.184.150]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Apr 2021 17:34:10 -0700 From: Umesh Nerlige Ramappa To: intel-gfx@lists.freedesktop.org Subject: [PATCH 1/1] i915/query: Correlate engine and cpu timestamps with better accuracy Date: Wed, 28 Apr 2021 17:34:10 -0700 Message-Id: <20210429003410.69754-2-umesh.nerlige.ramappa@intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210429003410.69754-1-umesh.nerlige.ramappa@intel.com> References: <20210429003410.69754-1-umesh.nerlige.ramappa@intel.com> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dri-devel@lists.freedesktop.org, jason@jlekstrand.net Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Perf measurements rely on CPU and engine timestamps to correlate events of interest across these time domains. Current mechanisms get these timestamps separately and the calculated delta between these timestamps lack enough accuracy. To improve the accuracy of these time measurements to within a few us, add a query that returns the engine and cpu timestamps captured as close to each other as possible. v2: (Tvrtko) - document clock reference used - return cpu timestamp always - capture cpu time just before lower dword of cs timestamp v3: (Chris) - use uncore-rpm - use __query_cs_timestamp helper v4: (Lionel) - Kernel perf subsytem allows users to specify the clock id to be used in perf_event_open. This clock id is used by the perf subsystem to return the appropriate cpu timestamp in perf events. Similarly, let the user pass the clockid to this query so that cpu timestamp corresponds to the clock id requested. v5: (Tvrtko) - Use normal ktime accessors instead of fast versions - Add more uApi documentation v6: (Lionel) - Move switch out of spinlock v7: (Chris) - cs_timestamp is a misnomer, use cs_cycles instead - return the cs cycle frequency as well in the query v8: - Add platform and engine specific checks v9: (Lionel) - Return 2 cpu timestamps in the query - captured before and after the register read v10: (Chris) - Use local_clock() to measure time taken to read lower dword of register and return it to user. v11: (Jani) - IS_GEN deprecated. User GRAPHICS_VER instead. v12: (Jason) - Split cpu timestamp array into timestamp and delta for cleaner API Signed-off-by: Umesh Nerlige Ramappa Reviewed-by: Lionel Landwerlin Reviewed-by: Lionel Landwerlin Reviewed-by: Jason Ekstrand --- drivers/gpu/drm/i915/i915_query.c | 148 ++++++++++++++++++++++++++++++ include/uapi/drm/i915_drm.h | 52 +++++++++++ 2 files changed, 200 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_query.c b/drivers/gpu/drm/i915/i915_query.c index fed337ad7b68..357c44e8177c 100644 --- a/drivers/gpu/drm/i915/i915_query.c +++ b/drivers/gpu/drm/i915/i915_query.c @@ -6,6 +6,8 @@ #include +#include "gt/intel_engine_pm.h" +#include "gt/intel_engine_user.h" #include "i915_drv.h" #include "i915_perf.h" #include "i915_query.h" @@ -90,6 +92,151 @@ static int query_topology_info(struct drm_i915_private *dev_priv, return total_length; } +typedef u64 (*__ktime_func_t)(void); +static __ktime_func_t __clock_id_to_func(clockid_t clk_id) +{ + /* + * Use logic same as the perf subsystem to allow user to select the + * reference clock id to be used for timestamps. + */ + switch (clk_id) { + case CLOCK_MONOTONIC: + return &ktime_get_ns; + case CLOCK_MONOTONIC_RAW: + return &ktime_get_raw_ns; + case CLOCK_REALTIME: + return &ktime_get_real_ns; + case CLOCK_BOOTTIME: + return &ktime_get_boottime_ns; + case CLOCK_TAI: + return &ktime_get_clocktai_ns; + default: + return NULL; + } +} + +static inline int +__read_timestamps(struct intel_uncore *uncore, + i915_reg_t lower_reg, + i915_reg_t upper_reg, + u64 *cs_ts, + u64 *cpu_ts, + u64 *cpu_delta, + __ktime_func_t cpu_clock) +{ + u32 upper, lower, old_upper, loop = 0; + + upper = intel_uncore_read_fw(uncore, upper_reg); + do { + *cpu_delta = local_clock(); + *cpu_ts = cpu_clock(); + lower = intel_uncore_read_fw(uncore, lower_reg); + *cpu_delta = local_clock() - *cpu_delta; + old_upper = upper; + upper = intel_uncore_read_fw(uncore, upper_reg); + } while (upper != old_upper && loop++ < 2); + + *cs_ts = (u64)upper << 32 | lower; + + return 0; +} + +static int +__query_cs_cycles(struct intel_engine_cs *engine, + u64 *cs_ts, u64 *cpu_ts, u64 *cpu_delta, + __ktime_func_t cpu_clock) +{ + struct intel_uncore *uncore = engine->uncore; + enum forcewake_domains fw_domains; + u32 base = engine->mmio_base; + intel_wakeref_t wakeref; + int ret; + + fw_domains = intel_uncore_forcewake_for_reg(uncore, + RING_TIMESTAMP(base), + FW_REG_READ); + + with_intel_runtime_pm(uncore->rpm, wakeref) { + spin_lock_irq(&uncore->lock); + intel_uncore_forcewake_get__locked(uncore, fw_domains); + + ret = __read_timestamps(uncore, + RING_TIMESTAMP(base), + RING_TIMESTAMP_UDW(base), + cs_ts, + cpu_ts, + cpu_delta, + cpu_clock); + + intel_uncore_forcewake_put__locked(uncore, fw_domains); + spin_unlock_irq(&uncore->lock); + } + + return ret; +} + +static int +query_cs_cycles(struct drm_i915_private *i915, + struct drm_i915_query_item *query_item) +{ + struct drm_i915_query_cs_cycles __user *query_ptr; + struct drm_i915_query_cs_cycles query; + struct intel_engine_cs *engine; + __ktime_func_t cpu_clock; + int ret; + + if (GRAPHICS_VER(i915) < 6) + return -ENODEV; + + query_ptr = u64_to_user_ptr(query_item->data_ptr); + ret = copy_query_item(&query, sizeof(query), sizeof(query), query_item); + if (ret != 0) + return ret; + + if (query.flags) + return -EINVAL; + + if (query.rsvd) + return -EINVAL; + + cpu_clock = __clock_id_to_func(query.clockid); + if (!cpu_clock) + return -EINVAL; + + engine = intel_engine_lookup_user(i915, + query.engine.engine_class, + query.engine.engine_instance); + if (!engine) + return -EINVAL; + + if (GRAPHICS_VER(i915) == 6 && + query.engine.engine_class != I915_ENGINE_CLASS_RENDER) + return -ENODEV; + + query.cs_frequency = engine->gt->clock_frequency; + ret = __query_cs_cycles(engine, + &query.cs_cycles, + &query.cpu_timestamp, + &query.cpu_delta, + cpu_clock); + if (ret) + return ret; + + if (put_user(query.cs_frequency, &query_ptr->cs_frequency)) + return -EFAULT; + + if (put_user(query.cpu_timestamp, &query_ptr->cpu_timestamp)) + return -EFAULT; + + if (put_user(query.cpu_delta, &query_ptr->cpu_delta)) + return -EFAULT; + + if (put_user(query.cs_cycles, &query_ptr->cs_cycles)) + return -EFAULT; + + return sizeof(query); +} + static int query_engine_info(struct drm_i915_private *i915, struct drm_i915_query_item *query_item) @@ -424,6 +571,7 @@ static int (* const i915_query_funcs[])(struct drm_i915_private *dev_priv, query_topology_info, query_engine_info, query_perf_config, + query_cs_cycles, }; int i915_query_ioctl(struct drm_device *dev, void *data, struct drm_file *file) diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index 6a34243a7646..0b4c27092d41 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -2230,6 +2230,10 @@ struct drm_i915_query_item { #define DRM_I915_QUERY_TOPOLOGY_INFO 1 #define DRM_I915_QUERY_ENGINE_INFO 2 #define DRM_I915_QUERY_PERF_CONFIG 3 + /** + * Query Command Streamer timestamp register. + */ +#define DRM_I915_QUERY_CS_CYCLES 4 /* Must be kept compact -- no holes and well documented */ /** @@ -2397,6 +2401,54 @@ struct drm_i915_engine_info { __u64 rsvd1[4]; }; +/** + * struct drm_i915_query_cs_cycles + * + * The query returns the command streamer cycles and the frequency that can be + * used to calculate the command streamer timestamp. In addition the query + * returns a set of cpu timestamps that indicate when the command streamer cycle + * count was captured. + */ +struct drm_i915_query_cs_cycles { + /** Engine for which command streamer cycles is queried. */ + struct i915_engine_class_instance engine; + + /** Must be zero. */ + __u32 flags; + + /** + * Command streamer cycles as read from the command streamer + * register at 0x358 offset. + */ + __u64 cs_cycles; + + /** Frequency of the cs cycles in Hz. */ + __u64 cs_frequency; + + /** + * CPU timestamp in ns. The timestamp is captured before reading the + * cs_cycles register using the reference clockid set by the user. + */ + __u64 cpu_timestamp; + + /** + * Time delta in ns captured around reading the lower dword of the + * cs_cycles register. + */ + __u64 cpu_delta; + + /** + * Reference clock id for CPU timestamp. For definition, see + * clock_gettime(2) and perf_event_open(2). Supported clock ids are + * CLOCK_MONOTONIC, CLOCK_MONOTONIC_RAW, CLOCK_REALTIME, CLOCK_BOOTTIME, + * CLOCK_TAI. + */ + __s32 clockid; + + /** Must be zero. */ + __u32 rsvd; +}; + /** * struct drm_i915_query_engine_info *