When I run top -bi, where the parameter -i means ignore idle processes, the resulted list(see below) of processes are either R or D, although there're S processes at that time.So, why uninterruptible sleep is not counted as idle? And, it seems that load average equals the number of R processes plus the number of D processes?top - 17:47:44 up 141 days, 14:29,  2 users,  load average: 4.10, 4.18, 4.17Tasks: 224 total,   1 running, 223 sleeping,   0 stopped,   0 zombieCpu(s):  0.1%us,  0.4%sy,  0.0%ni, 87.2%id, 12.3%wa,  0.0%hi,  0.0%si,  0.0%stMem:  16432240k total, 16345816k used,    86424k free,  4934652k buffersSwap: 16386292k total,     6996k used, 16379296k free,    71432k cachedPID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                                             7479 root      18   0 1357m 1.1g  904 D    1  7.0  10:27.86 rsync                                                               7463 root      18   0 1315m 1.0g  840 D    1  6.6   9:45.83 rsync                                                               7469 root      18   0 1088m 889m  840 D    0  5.5   8:10.20 rsync                                                               7524 root      18   0 1106m 895m  840 D    0  5.6   8:13.60 rsync                                                               30958 root      15   0 12720 1148  788 R    0  0.0   0:01.07 top
Why uninterruptible sleep is not counted as IDLE?
process;top;load