cpuRateCtl.c

#include <Windows.h>
#include <stdio.h>

int main(int argc, char **argv){
	
	if (argc < 3) {
		printf("<pid> <percentage> arguments required\n");
		exit(0);
	}

	DWORD pid = atoi(argv[1]);
	DWORD pct = atoi(argv[2]);

	HANDLE ph = OpenProcess(PROCESS_ALL_ACCESS, FALSE, pid);
	if (ph == NULL) {
		printf("open for pid %u failed (%u)\n", pid, GetLastError());
		exit(0);
	}

	HANDLE jh = CreateJobObject(NULL, NULL);
	if (jh == NULL) {
		printf("CreateJobObject() failed (%u)\n", GetLastError());
		exit(0);
	}

	BOOL r = AssignProcessToJobObject(jh, ph);
	if (r == 0) {
		printf("AssignProcessToJobObject() failed (%u)\n", GetLastError());
		exit(0);
	}

	JOBOBJECT_CPU_RATE_CONTROL_INFORMATION jc;

	jc.ControlFlags = JOB_OBJECT_CPU_RATE_CONTROL_ENABLE | JOB_OBJECT_CPU_RATE_CONTROL_HARD_CAP;
	jc.CpuRate = pct * 100;

	r = SetInformationJobObject(jh, JobObjectCpuRateControlInformation, &jc, sizeof(jc));
	if (r == 0) {
		printf("SetInformationJobObject() failed (%u)\n", GetLastError());
		exit(0);
	}
}