新手学堂 Linux操作系统中关于负载的定义

//kernel/timer.c

1254 active_tasks = count_active_tasks();

1256 CALC_LOAD(avenrun[0], EXP_1, active_tasks);

1257 CALC_LOAD(avenrun[1], EXP_5, active_tasks);

1258 CALC_LOAD(avenrun[2], EXP_15, active_tasks);

//include/linux/sched.h

 110 #define FSHIFT      11     /* nr of bits of precision */

111 #define FIXED_1  (1<
112 #define LOAD_FREQ (5*HZ) /* 5 sec intervals */

113 #define EXP_1     1884     /* 1/exp(5sec/1min) as fixed-point */

114 #define EXP_5     2014     /* 1/exp(5sec/5min) */

115 #define EXP_15    2037     /* 1/exp(5sec/15min) */

117 #define CALC_LOAD(load,exp,n) \

118     load *= exp; \

119     load += n*(FIXED_1-exp); \

120     load >>= FSHIFT;