internal static void SetCustomThreadAffinity(PoolOfThreads.PooledThread pooledThread)
{
ChangeThreadAffinityWithRetries(pooledThread.CurrentProcess, currentAffinity =>
{
SetCustomThreadAffinityInternal(pooledThread, currentAffinity);
});
}
internal static bool ResetThreadAffinity(PoolOfThreads.PooledThread pooledThread)
{
_customAffinityThreads.TryRemove(pooledThread);
return(ChangeThreadAffinityWithRetries(pooledThread.CurrentProcess, currentAffinity =>
{
SetThreadAffinity(pooledThread, currentAffinity);
}));
}
private static void SetThreadAffinity(PoolOfThreads.PooledThread pooledThread, long affinity)
{
if (PlatformDetails.RunningOnPosix == false)
{
// windows
pooledThread.CurrentProcessThread.ProcessorAffinity = new IntPtr(affinity);
return;
}
if (PlatformDetails.RunningOnLinux)
{
var ulongAffinity = (ulong)affinity;
var result = Syscall.sched_setaffinity((int)pooledThread.CurrentUnmanagedThreadId, new IntPtr(sizeof(ulong)), ref ulongAffinity);
if (result != 0)
{
throw new InvalidOperationException(
$"Failed to set affinity for thread: {pooledThread.CurrentUnmanagedThreadId}, " +
$"affinity: {affinity}, result: {result}, error: {Marshal.GetLastWin32Error()}");
}
}
}
private static void SetCustomThreadAffinityInternal(PoolOfThreads.PooledThread pooledThread, long currentAffinity)
{
var numberOfCoresToReduce = pooledThread.NumberOfCoresToReduce;
var threadMask = pooledThread.ThreadMask;
if (numberOfCoresToReduce <= 0 && threadMask == null)
{
_customAffinityThreads.TryRemove(pooledThread);
return;
}
_customAffinityThreads.TryAdd(pooledThread);
// we can't reduce the number of cores to a zero or negative number, in this case, just use the processor cores
if (threadMask == null && Bits.NumberOfSetBits(currentAffinity) <= numberOfCoresToReduce)
{
SetThreadAffinity(pooledThread, currentAffinity);
return;
}
if (threadMask == null)
{
for (int i = 0; i < numberOfCoresToReduce; i++)
{
// remove the N least significant bits
// we do that because it is typical that the first cores (0, 1, etc) are more
// powerful and we want to keep them for other things, such as request processing
currentAffinity &= currentAffinity - 1;
}
}
else
{
currentAffinity &= threadMask.Value;
}
SetThreadAffinity(pooledThread, currentAffinity);
}
