C# 为什么performanceCounter的NextValue调用会更改线程关联掩码
我有一个C#项目,我必须访问处理器的当前工作负载,并确保在处理器的每个内核上运行特定代码。我的问题是,访问处理器的工作负载似乎会阻止我正确分配线程关联掩码。我这里有一些代码,说明了问题:C# 为什么performanceCounter的NextValue调用会更改线程关联掩码,c#,multithreading,performancecounter,affinity,setthreadaffinitymask,C#,Multithreading,Performancecounter,Affinity,Setthreadaffinitymask,我有一个C#项目,我必须访问处理器的当前工作负载,并确保在处理器的每个内核上运行特定代码。我的问题是,访问处理器的工作负载似乎会阻止我正确分配线程关联掩码。我这里有一些代码,说明了问题: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Runtime.InteropServices; using System.Diagnostics; names
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.Diagnostics;
namespace KernelAffinitySpike
{
class Program
{
[DllImport("kernel32.dll", SetLastError = true)]
private static extern UIntPtr SetThreadAffinityMask(IntPtr hThread, UIntPtr dwThreadAffinityMask);
[DllImport("kernel32.dll", SetLastError = true)]
private static extern IntPtr GetCurrentThread();
private static PerformanceCounter cpuUsage;
private static UIntPtr oldMask, newMask, testMask; // thread-level processor affinity masks.
static void Main(string[] args)
{
InitPerformanceCounter();
Console.WriteLine("Pre: thread affinity: " + CurrentThreadAffinityMask());
if (AllKernelsAccessible())
Console.WriteLine("Pre: all kernels accessible");
else
{
Console.Write("Pre: some kernels not accessible: ");
foreach (UInt32 kernel in InaccessibleKernels())
Console.Write(kernel + " ");
Console.WriteLine();
}
float load = cpuUsage.NextValue();
Console.WriteLine("Post: thread affinity: " + CurrentThreadAffinityMask());
if (AllKernelsAccessible())
Console.WriteLine("Post: all kernels accessible");
else
{
Console.Write("Post: some kernels not accessible: ");
foreach (UInt32 kernel in InaccessibleKernels())
Console.Write(kernel + " ");
Console.WriteLine();
}
Console.ReadLine();
}
static void InitPerformanceCounter()
{
cpuUsage = new PerformanceCounter();
cpuUsage.CategoryName = "Processor";
cpuUsage.CounterName = "% Processor Time";
cpuUsage.InstanceName = "_Total";
}
static UInt32 CurrentThreadAffinityMask()
{
oldMask = SetThreadAffinityMask(GetCurrentThread(), (UIntPtr) 3); // 3 just enables all processors on a dual core. I'm only interested in the return value.
SetThreadAffinityMask(GetCurrentThread(), oldMask);
return (UInt32) oldMask;
}
static List<UInt32> InaccessibleKernels()
{
List<UInt32> inaccessible = new List<UInt32>();
for (int i = 0; i < Environment.ProcessorCount; i++)
{
newMask = (UIntPtr)(1 << i);
oldMask = SetThreadAffinityMask(GetCurrentThread(), newMask);
testMask = SetThreadAffinityMask(GetCurrentThread(), oldMask);
if (newMask != testMask)
inaccessible.Add((UInt32) newMask);
}
return inaccessible;
}
static bool AllKernelsAccessible()
{
return InaccessibleKernels().Count == 0;
}
}
}
因此,似乎cpuUsage.NextValue调用以某种方式更改了线程关联掩码,也使得无法将掩码更改为1。如果Nextvalue调用正在聚合每个内核的性能计数,那么它必须以某种方式与线程关联掩码交互,这是有意义的,但我不理解,为什么它会影响线程关联掩码的未来更改。有人对此问题有解释或解决方法吗?这里是
似乎是微软尚未解决的问题
下面是问题的陈述-性能计数器更改线程的关联性
他们建议打电话给SetThreadAffinity。)显然,他们的解决方案是行不通的
Pre: thread affinity: 3
Pre: all kernels accessible
Post: thread affinity: 2
Post: some kernels not accessible: 1