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Add basic code sampler for macOS
1 parent b290c6f commit 829faa8

9 files changed

+537
-1
lines changed

‎src/Ultra.Sampler/Ultra.Sampler.csproj

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<Project Sdk="Microsoft.NET.Sdk">
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<PropertyGroup>
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<TargetFramework>net8.0</TargetFramework>
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<ImplicitUsings>enable</ImplicitUsings>
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<Nullable>enable</Nullable>
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<AllowUnsafeBlocks>true</AllowUnsafeBlocks>
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<IsPackable>false</IsPackable>
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</PropertyGroup>
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<ItemGroup>
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<InternalsVisibleTo Include="Ultra.Tests"/>
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</ItemGroup>
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</Project>

‎src/Ultra.Sampler/UltraSampler.cs

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using System.Diagnostics;
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using System.Runtime.CompilerServices;
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using System.Runtime.InteropServices;
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namespace Ultra.Sampler;
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using static libSystem;
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public static class UltraSampler
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{
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private static readonly object Lock = new();
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private static Thread? _thread;
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private static bool _stopped;
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private const int MaximumFrames = 65536;
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[UnmanagedCallersOnly(CallConvs = [typeof(CallConvCdecl)], EntryPoint = "ultra_sampler_start")]
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internal static void NativeStart() => Start();
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[UnmanagedCallersOnly(CallConvs = [typeof(CallConvCdecl)], EntryPoint = "ultra_sampler_stop")]
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internal static void NativeStop() => Stop();
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public static void Start()
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{
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lock (Lock)
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{
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if (_thread is not null) return;
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_thread = new Thread(RunImpl)
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{
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IsBackground = true,
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Name = "Ultra-Sampler",
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Priority = ThreadPriority.Highest
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};
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_thread.Start();
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}
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}
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public static void Stop()
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{
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lock (Lock)
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{
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if (_thread is null) return;
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_stopped = true;
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_thread.Join();
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_thread = null;
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_stopped = false;
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}
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}
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private static void RunImpl()
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{
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try
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{
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task_for_pid(mach_task_self(), Process.GetCurrentProcess().Id, out var rootTask)
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.ThrowIfError("task_for_pid");
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pthread_threadid_np(0, out var currentThreadId)
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.ThrowIfError("pthread_threadid_np");
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var frames = GC.AllocateUninitializedArray<ulong>(MaximumFrames, pinned: true);
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while (!_stopped)
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{
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if (UltraSamplerSource.Log.IsEnabled())
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{
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Sample(rootTask, currentThreadId, frames);
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}
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// Sleep for 1ms
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Thread.Sleep(1);
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}
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}
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catch (Exception ex)
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{
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Trace.TraceError($"Ultra-Sampler unexpected exception while sampling: {ex}");
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}
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}
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private static unsafe void Sample(mach_port_t rootTask, ulong currentThreadId, Span<ulong> frames)
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{
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mach_port_t* taskList;
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task_threads(rootTask, &taskList, out uint taskCount)
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.ThrowIfError("task_threads");
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thread_identifier_info threadInfo = new();
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ulong* pFrames = (ulong*)Unsafe.AsPointer(ref frames[0]);
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for (var i = 0; i < taskCount; i++)
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{
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var threadPort = taskList[i];
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try
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{
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int threadInfoCount = THREAD_IDENTIFIER_INFO_COUNT;
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thread_info(threadPort, THREAD_IDENTIFIER_INFO, out threadInfo, ref threadInfoCount)
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.ThrowIfError("thread_info");
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//var thread_t = pthread_from_mach_thread_np(threadPort);
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//if (thread_t != 0)
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//{
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// pthread_getname_np(thread_t, nameBuffer, 256)
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// .ThrowIfError("pthread_getname_np");
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// Console.WriteLine($"Thread ID: {threadInfo.thread_id} Name: {Marshal.PtrToStringAnsi((IntPtr)nameBuffer)}");
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//}
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//else
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//{
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// Console.WriteLine($"Thread ID: {threadInfo.thread_id}");
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//}
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if (threadInfo.thread_id == currentThreadId) continue;
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thread_suspend(taskList[i])
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.ThrowIfError("thread_suspend");
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try
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{
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arm_thread_state64_t armThreadState = new arm_thread_state64_t();
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int armThreadStateCount = ARM_THREAD_STATE64_COUNT;
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thread_get_state(threadPort, ARM_THREAD_STATE64, (nint)(void*)&armThreadState, ref armThreadStateCount)
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.ThrowIfError("thread_get_state");
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//Console.WriteLine($"sp: 0x{armThreadState.__sp:X8}, fp: 0x{armThreadState.__fp:X8}, lr: 0x{armThreadState.__lr:X8}");
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WalkCallStack(armThreadState.__sp, armThreadState.__fp, armThreadState.__lr, pFrames);
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}
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finally
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{
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thread_resume(threadPort)
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.ThrowIfError("thread_resume");
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}
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}
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catch (Exception ex)
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{
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Trace.TraceError($"Ultra-Sampler unexpected exception while sampling thread #{threadInfo.thread_id}: {ex}");
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}
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}
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}
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private static unsafe void WalkCallStack(ulong sp, ulong fp, ulong lr, ulong* frames)
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{
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int frameIndex = 0;
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while (fp != 0 && frameIndex < MaximumFrames)
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{
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frames[frameIndex++] = lr;
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//sp = fp + 16;
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lr = *(ulong*)(fp + 8);
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fp = *(ulong*)fp;
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}
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UltraSamplerSource.Log.Callstack(frames, frameIndex);
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}
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}

‎src/Ultra.Sampler/UltraSamplerParser.cs

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// Copyright (c) Alexandre Mutel. All rights reserved.
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// Licensed under the BSD-Clause 2 license.
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// See license.txt file in the project root for full license information.
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namespace Ultra.Sampler;
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public static class UltraSamplerParser
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{
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public const string Name = "Ultra-Sampler";
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public const string IdAsString = "04E4DCBF-494F-4A77-B55E-F5C041A92F56";
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public static readonly Guid Id = new(IdAsString);
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public const int CallStackEvent = 1;
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}

‎src/Ultra.Sampler/UltraSamplerSource.cs

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// Copyright (c) Alexandre Mutel. All rights reserved.
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// Licensed under the BSD-Clause 2 license.
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// See license.txt file in the project root for full license information.
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using System.Diagnostics.Tracing;
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using System.Runtime.CompilerServices;
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namespace Ultra.Sampler;
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[EventSource(Name = UltraSamplerParser.Name, Guid = UltraSamplerParser.IdAsString)]
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public class UltraSamplerSource : EventSource
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{
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public static readonly UltraSamplerSource Log = new();
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private UltraSamplerSource()
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{
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}
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[Event(UltraSamplerParser.CallStackEvent, Level = EventLevel.Verbose)]
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[SkipLocalsInit]
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[MethodImpl(MethodImplOptions.NoInlining)]
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public unsafe void Callstack(ulong* pFrames, int count)
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{
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if (IsEnabled())
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{
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Unsafe.SkipInit(out EventSource.EventData evt);
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evt.DataPointer = (nint)pFrames;
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evt.Size = count * sizeof(ulong);
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WriteEventCore(UltraSamplerParser.CallStackEvent, 1, &evt);
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}
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}
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}

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