rocm-systems/source/include/rocprofiler-sdk/pc_sampling.h

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#pragma once

#include <rocprofiler-sdk/agent.h>
#include <rocprofiler-sdk/defines.h>
#include <rocprofiler-sdk/fwd.h>

ROCPROFILER_EXTERN_C_INIT

/**
 * @defgroup PC_SAMPLING_SERVICE PC Sampling
 * @brief Enabling PC (Program Counter) Sampling for GPU Activity
 * @{
 */

/**
 * @brief Function used to configure the PC sampling service on the GPU agent with @p agent_id.
 *
 * Prerequisites are the following:
 * - The client must create a context and supply its @p context_id. By using this context,
 *   the client can start/stop PC sampling on the agent. For more information,
 *   please @see rocprofiler_start_context/rocprofiler_stop_context.
 * - The user must create a buffer and supply its @p buffer_id. Rocprofiler-SDK uses the buffer
 *   to deliver the PC samples to the client. For more information about the data delivery,
 *   please @see rocprofiler_create_buffer and @see rocprofiler_buffer_tracing_cb_t.
 *
 * Before calling this function, we recommend querying PC sampling configurations
 * supported by the GPU agent via the @see rocprofiler_query_pc_sampling_agent_configurations.
 * The client chooses the @p method, @p unit, and @p interval to match one of the
 * available configurations. Note that the @p interval must belong to the range of values
 * [available_config.min_interval, available_config.max_interval],
 * where available_config is the instance of the @see rocprofiler_pc_sampling_configuration_s
 * supported/available at the moment.
 *
 * Rocprofiler-SDK checks whether the requsted configuration is actually supported
 * at the moment of calling this function. If the answer is yes, it returns
 * the @see ROCPROFILER_STATUS_SUCCESS. Otherwise, it notifies the client about the
 * rejection reason via the returned status code. For more information
 * about the status codes, please @see rocprofiler_status_t.
 *
 * There are a few constraints a client's code needs to be aware of.
 *
 * Constraint1: A GPU agent can be configured to support at most one running PC sampling
 * configuration at any time, which implies some of the consequences described below.
 * After the tool configures the PC sampling with one of the available configurations,
 * rocprofiler-SDK guarantees that this configuration will be valid for the tool's
 * lifetime. The tool can start and stop the configured PC sampling service whenever convenient.
 *
 * Constraint2: Since the same GPU agent can be used by multiple processes concurrently,
 * Rocprofiler-SDK cannot guarantee the exclusive access to the PC sampling capability.
 * The consequence is the following scenario. The tool TA that belongs to the process PA,
 * calls the @see rocprofiler_query_pc_sampling_agent_configurations that returns the
 * two supported configurations CA and CB by the agent. Then the tool TB of the process PB,
 * configures the PC sampling on the same agent by using the configuration CB.
 * Subsequently, the TA tries configuring the CA on the agent, and it fails.
 * To point out that this case happened, we introduce a special status code
 * @see ROCPROFILER_STATUS_ERROR_NOT_AVAILABLE.
 * When this status code is observed by the tool TA, it queries all available configurations again
 * by calling @see rocprofiler_query_pc_sampling_agent_configurations,
 * that returns only CB this time. The tool TA can choose CB, so that both
 * TA and TB use the PC sampling capability in the separate processes.
 * Both TA and TB receives samples generated by the kernels launched by the
 * corresponding processes PA and PB, respectively.
 *
 * Constraint3: Rocprofiler-SDK allows only one context to contain the configured PC sampling
 * service within the process, that implies that at most one of the loaded tools can use PC
 * sampling. One context can contains multiple PC sampling services configured for different GPU
 * agents.
 *
 * Constraint4: PC sampling feature is not available within the ROCgdb.
 *
 * @param [in] context_id - id of the context used for starting/stopping PC sampling service
 * @param [in] agent_id   - id of the agent on which caller tries using PC sampling capability
 * @param [in] method     - the type of PC sampling the caller tries to use on the agent.
 * @param [in] unit       - The unit appropriate to the PC sampling type/method.
 * @param [in] interval   - frequency at which PC samples are generated
 * @param [in] buffer_id  - id of the buffer used for delivering PC samples
 * @return ::rocprofiler_status_t
 * @retval ::ROCPROFILER_STATUS_SUCCESS PC sampling service configured successfully
 * @retval ::ROCPROFILER_STATUS_ERROR_NOT_AVAILABLE One of the scenarios is present:
 * 1. PC sampling is already configured with configuration different than requested,
 * 2. PC sampling is requested from a process that runs within the ROCgdb.
 * 3. HSA runtime does not support PC sampling.
 * @retval ::ROCPROFILER_STATUS_ERROR_INCOMPATIBLE_KERNEL the amdgpu driver installed on the system
 * does not support the PC sampling feature
 * @retval ::ROCPROFILER_STATUS_ERROR a general error caused by the amdgpu driver
 *
 */
rocprofiler_status_t ROCPROFILER_API
rocprofiler_configure_pc_sampling_service(rocprofiler_context_id_t         context_id,
                                          rocprofiler_agent_id_t           agent_id,
                                          rocprofiler_pc_sampling_method_t method,
                                          rocprofiler_pc_sampling_unit_t   unit,
                                          uint64_t                         interval,
                                          rocprofiler_buffer_id_t          buffer_id);

/**
 * @brief PC sampling configuration supported by a GPU agent.
 */
typedef struct
{
    uint64_t                         size;  ///< Size of this struct
    rocprofiler_pc_sampling_method_t method;
    rocprofiler_pc_sampling_unit_t   unit;
    size_t                           min_interval;
    size_t                           max_interval;
    uint64_t                         flags;  /// for future use

    /// @var method
    /// @brief Sampling method supported by the GPU agent.
    /// Currently, it can take one of the following two values:
    /// - ::ROCPROFILER_PC_SAMPLING_METHOD_HOST_TRAP: a background host kernel thread
    /// periodically interrupts waves execution on the GPU to generate PC samples
    /// - ::ROCPROFILER_PC_SAMPLING_METHOD_STOCHASTIC: performance monitoring hardware
    /// on the GPU periodically interrupts waves to generate PC samples.
    /// @var unit
    /// @brief A unit used to specify the interval of the @ref method for samples generation.
    /// @var min_interval
    /// @brief the highest possible frequencey for generating samples using @ref method.
    /// @var max_interva
    /// @brief the lowest possible frequency for generating samples using @ref method

} rocprofiler_pc_sampling_configuration_t;

/**
 * @brief Rocprofiler SDK's callback function to deliver the list of available PC
 * sampling configurations upon the call to the
 * @ref rocprofiler_query_pc_sampling_agent_configurations.
 *
 * @param[out] configs - The array of PC sampling configurations supported by the agent
 * at the moment of invoking @ref rocprofiler_query_pc_sampling_agent_configurations.
 * @param[out] num_config - The number of configurations contained in the underlying array
 * @p configs.
 * In case the GPU agent does not support PC sampling, the value is 0.
 * @param[in] user_data - client's private data passed via
 * @ref rocprofiler_query_pc_sampling_agent_configurations
 * @return ::rocprofiler_status_t
 */
typedef rocprofiler_status_t (*rocprofiler_available_pc_sampling_configurations_cb_t)(
    const rocprofiler_pc_sampling_configuration_t* configs,
    size_t                                         num_config,
    void*                                          user_data);

/**
 * @brief Query PC Sampling Configuration.
 *
 * Lists PC sampling configurations a GPU agent with @p agent_id supports at the moment
 * of invoking the function. Delivers configurations via @p cb.
 * In case the PC sampling is configured on the GPU agent, the @p cb delivers information
 * about the active PC sampling configuration.
 * In case the GPU agent does not support PC sampling capability,
 * the @p cb delivers none PC sampling configurations.
 *
 * @param [in] agent_id  - id of the agent for which available configurations will be listed
 * @param [in] cb        - User callback that delivers the available PC sampling configurations
 * @param [in] user_data - passed to the @p cb
 * @return ::rocprofiler_status_t
 * @retval ::ROCPROFILER_STATUS_ERROR_NOT_AVAILABLE One of the scenarios is present:
 * 1. PC sampling is requested from a process that runs within the ROCgdb.
 * 2. HSA runtime does not support PC sampling.
 * @retval ::ROCPROFILER_STATUS_ERROR_INCOMPATIBLE_KERNEL the amdgpu driver installed on the system
 * does not support the PC sampling feature.
 * @retval ::ROCPROFILER_STATUS_ERROR a general error caused by the amdgpu driver
 * @retval ::ROCPROFILER_STATUS_SUCCESS @p cb successfully finished
 */
rocprofiler_status_t ROCPROFILER_API
rocprofiler_query_pc_sampling_agent_configurations(
    rocprofiler_agent_id_t                                agent_id,
    rocprofiler_available_pc_sampling_configurations_cb_t cb,
    void*                                                 user_data) ROCPROFILER_NONNULL(2, 3);

/**
 * @brief The header of the @ref rocprofiler_pc_sampling_record_t, indicating
 * what fields of the @ref rocprofiler_pc_sampling_record_t instance are meaningful
 * for the sample.
 */
typedef struct
{
    uint8_t valid            : 1;  /// sample is valid
    uint8_t type             : 4;
    uint8_t has_stall_reason : 1;
    uint8_t has_wave_cnt     : 1;
    uint8_t reserved         : 1;  /// for future use

    /// @var type
    /// @brief The following values are possible:
    /// - 0 - reserved
    /// - 1 - host trap pc sample
    /// - 2 - stochastic pc sample
    /// - 3 - perfcounter (unsupported at the moment)
    /// - other values does not mean anything at the moment
    /// @var has_stall_reason
    /// @brief whether the sample contains information about the stall reason.
    /// If so, please @see rocprofiler_pc_sampling_snapshot_v1_t.
    /// @var has_wave_cnt
    /// @brief whether the @ref rocprofiler_pc_sampling_record_t::wave_count
    /// contains meaningful value
} rocprofiler_pc_sampling_header_v1_t;

/**
 * @brief TODO: provide the description
 */
typedef struct
{
    uint32_t dual_issue_valu   : 1;
    uint32_t inst_type         : 4;
    uint32_t reason_not_issued : 7;
    uint32_t arb_state_issue   : 10;
    uint32_t arb_state_stall   : 10;
} rocprofiler_pc_sampling_snapshot_v1_t;

// TODO: The definition of this structure might change over time
// to reduce the space needed to represent a single sample.
/**
 * @brief ROCProfiler PC Sampling Record corresponding to the interrupted wave.
 */
typedef struct
{
    uint64_t                            size;  ///< Size of this struct
    rocprofiler_pc_sampling_header_v1_t flags;
    uint8_t                             chiplet;  /// chiplet index
    uint8_t                             wave_id;  /// wave identifier within the workgroup
    uint8_t                             wave_issued : 1;
    uint8_t                             reserved    : 7;  /// reserved 7 bits, must be zero
    uint32_t                            hw_id;            /// compute unit identifier
    uint64_t                     pc;  /// Program counter of the wave of the moment of interruption
    uint64_t                     exec_mask;
    rocprofiler_dim3_t           workgroup_id;  /// wave coordinates within the workgroup
    uint32_t                     wave_count;
    uint64_t                     timestamp;  /// timestamp when sample is generated
    rocprofiler_correlation_id_t correlation_id;
    rocprofiler_pc_sampling_snapshot_v1_t
             snapshot;   /// @see ::rocprofiler_pc_sampling_snapshot_v1_t
    uint32_t reserved2;  /// for future use

    /// @var flags
    /// @brief indicates what fields of this struct are meaningful for the represented sample.
    /// The values depend on what the underlying GPU agent architecture supports.
    /// @var wave_issue
    /// @brief indicates whether the wave is issueing the instruction represented by the @ref pc
    /// @var exec_mask
    /// @brief shows how many SIMD lanes of the wave were executing the instruction
    /// represented by the @ref pc. Useful to understand thread-divergance within the wave
    /// @var wave_count
    /// @brief number of active waves on the CU at the moment of sample generation
    /// @var correlation_id
    /// @brief correlation id of the API call that initiated kernel launch.
    /// The interrupted wave is executed as part of the kernel.
} rocprofiler_pc_sampling_record_t;

/**
 * @brief Marker representing code object loading event.
 *
 * @see rocprofiler_callback_tracing_code_object_load_data_t
 * for more information
 */
typedef struct
{
    uint64_t size;            ///< Size of this struct
    uint64_t code_object_id;  /// unique code object identifier
} rocprofiler_pc_sampling_code_object_load_marker_t;

/**
 * @brief Marker representing code object unloading event.
 *
 * @see rocprofiler_callback_tracing_code_object_load_data_t
 * for more information
 */
typedef struct
{
    uint64_t size;            ///< Size of this struct
    uint64_t code_object_id;  /// unique code object identifier
} rocprofiler_pc_sampling_code_object_unload_marker_t;

/** @} */

ROCPROFILER_EXTERN_C_FINI

ROCPROFILER_CXX_CODE(
    static_assert(sizeof(rocprofiler_pc_sampling_record_t) == 80,
                  "Increasing the size of the pc sampling record is not permitted."));

ROCPROFILER_CXX_CODE(static_assert(offsetof(rocprofiler_pc_sampling_record_t, chiplet) == 9 &&
                                       offsetof(rocprofiler_pc_sampling_record_t, reserved2) == 76,
                                   "PC sampling record layout changed."));