From mboxrd@z Thu Jan 1 00:00:00 1970 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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 76DE3C433ED for ; Thu, 29 Apr 2021 08:34:36 +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 0C74661158 for ; Thu, 29 Apr 2021 08:34:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0C74661158 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7B3376EDB2; Thu, 29 Apr 2021 08:34:35 +0000 (UTC) Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by gabe.freedesktop.org (Postfix) with ESMTPS id 985796EDB2; Thu, 29 Apr 2021 08:34:34 +0000 (UTC) IronPort-SDR: xx8t5FZVxfcR2IJqFrnjauA8+6J5VBc2T4o3k47oLHFJdnkBRlHBVveI/IetktGue3cVLRspEj HoSDq0TrQ7yw== X-IronPort-AV: E=McAfee;i="6200,9189,9968"; a="197005300" X-IronPort-AV: E=Sophos;i="5.82,258,1613462400"; d="scan'208";a="197005300" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Apr 2021 01:34:33 -0700 IronPort-SDR: tz/Rtk61MU5x5L21iO4Zaw2PbwZStd4joVnaxY0T1oIKEXpMZ1meovRbfN2tr7oTLL8SUBDkIn QyD+n5zp2ijw== X-IronPort-AV: E=Sophos;i="5.82,258,1613462400"; d="scan'208";a="430740914" Received: from ssuryana-mobl.ger.corp.intel.com (HELO [10.249.44.155]) ([10.249.44.155]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Apr 2021 01:34:32 -0700 To: Umesh Nerlige Ramappa , intel-gfx@lists.freedesktop.org References: <20210429003410.69754-1-umesh.nerlige.ramappa@intel.com> <20210429003410.69754-2-umesh.nerlige.ramappa@intel.com> From: Lionel Landwerlin Organization: Intel Corporation (UK) Ltd. - Co. Reg. #1134945 - Pipers Way, Swindon SN3 1RJ Message-ID: <5b2218d4-10b5-11b8-699b-5564e89d3295@intel.com> Date: Thu, 29 Apr 2021 11:34:30 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <20210429003410.69754-2-umesh.nerlige.ramappa@intel.com> Content-Language: en-US Subject: Re: [Intel-gfx] [PATCH 1/1] i915/query: Correlate engine and cpu timestamps with better accuracy X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dri-devel@lists.freedesktop.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On 29/04/2021 03:34, Umesh Nerlige Ramappa wrote: > 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 Thanks for the update : Reviewed-by: Lionel Landwerlin > --- > 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 > * _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx