ProfilerUnsafeUtility.FlowEvent

Parameters

Description

Add flow event to a Profiler sample.

Use Profiler flow events to highlight the dependencies between task execution on different threads.

Flow event works in conjunction with ProfilerMarker.

using System;
using System.Threading;
using Unity.Profiling;
using Unity.Profiling.LowLevel;
using Unity.Profiling.LowLevel.Unsafe;

public class Example
{
    public const int k_NumberOfTasks = 4;

    static readonly ProfilerMarker k_ScheduleParallelTasksMarker = new ProfilerMarker("Schedule Parallel Tasks");
    static readonly ProfilerMarker k_ParallelTaskMarker = new ProfilerMarker("Parallel Task");
    static readonly ProfilerMarker k_TaskSyncMarker = new ProfilerMarker("Sync Task");

    static void EmitFlowEventAndChainThread(uint flowId)
    {
        // Mark the next k_ParallelTaskMarker as a beginning of the flow
        ProfilerUnsafeUtility.FlowEvent(flowId, ProfilerFlowEventType.ParallelNext);
        using (k_ParallelTaskMarker.Auto())
        {
            // Do work
        }
    }

    static void ScheduleParallelTask()
    {
        uint flowId;
        var threads = new Thread[k_NumberOfTasks];
        using (k_ScheduleParallelTasksMarker.Auto())
        {
            flowId = ProfilerUnsafeUtility.CreateFlow(ProfilerUnsafeUtility.CategoryScripts);
            // Mark the parent k_ScheduleParallelTasksMarker as a beginning of the flow
            ProfilerUnsafeUtility.FlowEvent(flowId, ProfilerFlowEventType.Begin);
            for (var i = 0; i < k_NumberOfTasks; ++i)
            {
                var thread = new Thread(() => EmitFlowEventAndChainThread(flowId));
                thread.Start();
                threads[i] = thread;
            }
        }

        using (k_TaskSyncMarker.Auto())
        {
            // Mark the parent k_TaskSyncMarker as a beginning of the flow
            ProfilerUnsafeUtility.FlowEvent(flowId, ProfilerFlowEventType.End);
            for (var i = 0; i < k_NumberOfTasks; ++i)
                threads[i].Join();
        }
    }
}

You must use FlowEvent together with a ProfilerMarker.

To mark the sample as a beginning or end of a flow, use FlowEvent with ProfilerFlowEventType.Begin and ProfilerFlowEventType.End events within a scope that is instrumented with ProfilerMarker.Begin and ProfilerMarker.End, or within the using scope of ProfilerMarker.Auto.


To mark the sample as a flow continuation point, use FlowEvent with ProfilerFlowEventType.Next and ProfilerFlowEventType.ParallelNext before a call to ProfilerMarker.Begin or ProfilerMarker.Auto.

Note: Unity Job System automatically marks up job scheduling, execution and wait points.

Additional resources: CreateFlow, CPU Usage Profiler module.