private static unsafe void SetMaxCpuRate(Win32Job job, SessionSettings session, ulong systemAffinityMask)
{
if (session.CpuMaxRate > 0)
{
// Set CpuRate to a percentage times 100. For example, to let the job use 20% of the CPU,
// set CpuRate to 20 times 100, or 2,000.
uint finalCpuRate = session.CpuMaxRate * 100;
// CPU rate is set for the whole system so includes all the logical CPUs. When
// we have the CPU affinity set, we will divide the rate accordingly.
if (session.CpuAffinityMask != 0)
{
ulong affinity = systemAffinityMask & session.CpuAffinityMask;
uint numberOfSelectedCores = 0;
for (int i = 0; i < sizeof(ulong) * 8; i++)
{
numberOfSelectedCores += (affinity & (1UL << i)) == 0 ? 0u : 1u;
}
Debug.Assert(numberOfSelectedCores < Environment.ProcessorCount);
finalCpuRate /= ((uint)Environment.ProcessorCount / numberOfSelectedCores);
}
// configure CPU rate limit
var limitInfo = new JOBOBJECT_CPU_RATE_CONTROL_INFORMATION
{
ControlFlags = JOB_OBJECT_CPU_RATE_CONTROL.JOB_OBJECT_CPU_RATE_CONTROL_ENABLE |
JOB_OBJECT_CPU_RATE_CONTROL.JOB_OBJECT_CPU_RATE_CONTROL_HARD_CAP,
Anonymous = new JOBOBJECT_CPU_RATE_CONTROL_INFORMATION._Anonymous_e__Union {
CpuRate = finalCpuRate
}
};
var size = (uint)Marshal.SizeOf(limitInfo);
CheckWin32Result(PInvoke.SetInformationJobObject(job.JobHandle, JOBOBJECTINFOCLASS.JobObjectCpuRateControlInformation,
&limitInfo, size));
}
}
internal static extern bool QueryInformationJobObject(SafeJobObjectHandle hJob, JobObjectInformationClass JobObjectInfoClass, [Out] out JOBOBJECT_CPU_RATE_CONTROL_INFORMATION lpJobObjectInfo, int cbJobObjectInfoLength, IntPtr lpReturnLength);
internal static extern bool SetInformationJobObject(SafeJobObjectHandle hJob, JobObjectInformationClass JobObjectInfoClass, [In] ref JOBOBJECT_CPU_RATE_CONTROL_INFORMATION lpJobObjectInfo, int cbJobObjectInfoLength);