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;