import ctypesimport fnmatchimport osimport platformimport timeIOPRIO_GET_ARCH_SYSCALL = [ ('alpha', '*', 443), ('i*86', '*', 290), ('ia64*', '*', 1275), ('ppc*', '*', 274), ('s390*', '*', 283), ('sparc*', '*', 218), ('sh*', '*', 289), ('x86_64*', '32bit', 290), ('x86_64*', '64bit', 252),]IOPRIO_SET_ARCH_SYSCALL = [ ('alpha', '*', 442), ('i*86', '*', 289), ('ia64*', '*', 1274), ('ppc*', '*', 273), ('s390*', '*', 282), ('sparc*', '*', 196), ('sh*', '*', 288), ('x86_64*', '32bit', 289), ('x86_64*', '64bit', 251),]#查看本机的CPU架构类型和处理器位数def find_ioprio_syscall_number(syscall_list): arch = os.uname()[4] bits = platform.architecture()[0] for candidate_arch, candidate_bits, syscall_nr in syscall_list: if fnmatch.fnmatch(arch,candidate_arch) and fnmatch.fnmatch(bits,candidate_bits): return syscall_nr class IoprioSetError(Exception): def __init__(self,err): try: self.err = os.strerror(err) except TypeError: self.err = err__NR_ioprio_get = find_ioprio_syscall_number(IOPRIO_GET_ARCH_SYSCALL)__NR_ioprio_set = find_ioprio_syscall_number(IOPRIO_SET_ARCH_SYSCALL)#print __NR_ioprio_get,__NR_ioprio_settry: ctypes_handle = ctypes.CDLL(None, user_errno=True)except TypeError: ctypes_handle = ctypes.CDLL(None)syscall = ctypes_handle.syscall#定义几种I/O调度类别PRIORITY_CLASS = [None, 'rt', 'be', 'idle']IOPRIO_WHO_PROCESS = 1IOPRIO_CLASS_SHIFT = 13IOPRIO_PRIO_MASK = (1 << IOPRIO_CLASS_SHIFT) -1def ioprio_value(ioprio_class,ioprio_data): try: ioprio_class = PRIORITY_CLASS.index(ioprio_class) except ValueError: ioprio_class = PRIORITY_CLASS.index(None) return (ioprio_class << IOPRIO_CLASS_SHIFT) | ioprio_datadef ioprio_class(ioprio): return PRIORITY_CLASS[ioprio >> IOPRIO_CLASS_SHIFT]def ioprio_data(ioprio): return ioprio & IOPRIO_PRIO_MASKsched_getscheduler = ctypes_handle.sched_getschedulerSCHED_OTHER, SCHED_FIFO, SCHED_RR, SCHED_BATCH, SCHED_ISO, SCHED_IDLE = range(6)getpriority = ctypes_handle.getpriorityPRIO_PROCESS = 0#根据PID获得I/O调度类别和优先级def get_ioprio_from_sched(pid): scheduler = sched_getscheduler(pid) nice = getpriority(PRIO_PROCESS,pid) ioprio_nice = (nice + 20)/5 if scheduler in (SCHED_FIFO,SCHED_RR): return 'rt/%d' % ioprio_nice elif scheduler == SCHED_IDLE: return 'idle' else: return 'be/%d' % ioprio_nice def get(pid): if __NR_ioprio_get is None: return '?sys' ioprio = syscall(__NR_ioprio_get, IOPRIO_WHO_PROCESS, pid) if ioprio < 0: return '?err' prio_class = ioprio_class(ioprio) if not prio_class: return get_ioprio_from_sched(pid) if prio_class == 'idle': return prio_class return '%s/%d' % (prio_class, ioprio_data(ioprio))def set_ioprio(which, who, ioprio_class, ioprio_data): if __NR_ioprio_set is None: raise IoprioSetError('No ioprio_set syscall found') ioprio_val = ioprio_value(ioprio_class,ioprio_data) ret = syscall(__NR_ioprio_set, which, who, ioprio_val, use_errno=True) if ret < 0: try: err = ctypes.get_errno() except AttributeError: err = 'Unknown error (errno support not available before Python2.6)' raise IoprioSetError(err)def sort_key(key): if key[0] == '?': return -ord(key[1]) if '/' in key: if key.startswith('rt/'): shift = 0 elif key.startswith('be/'): shift = 1 prio = int(key.split('/')[1]) elif key == 'idle': shift =2 prio = 0 return (1 << (shift * IOPRIO_CLASS_SHIFT)) + priodef to_class_and_data(ioprio_str): if '/' in ioprio_str: split = ioprio_str.split('/') return (split[0], int(split[1])) elif ioprio_str == 'idle': return ('idle',0) return (None,None)#如果指定PID，则获取指定PID的I/O调度类别和优先级，不指定就获取当前进程的I/O调度类别和优先级if __name__ == '__main__': import sys if len(sys.argv) == 2: pid = int(sys.argv[1]) else: pid = os.getpid() print 'pid:', pid print 'ioprio:', get(pid) 输出结果:
$ python ioprio.py pid: 11628ioprio: be/4$ python ioprio.py 32600pid: 32600ioprio: be/4
这个程序涉及到Linux的I/O调度和进程调度的知识