As far as I know, the load average in top is the numbers of precess(threads) in running or uninterrupted sleep status, So it should be equal to (procs-r +1 )+ procs-b in vmstat, but in practice, this two number always have big gap. Any wrongs in my understanding, appreciate so much if some guys give me some guide.

top - 05:34:50 up 1 day, 20:56,  5 users,  load average: 2.83, 2.67, 1.62
Tasks:  79 total,   1 running,  78 sleeping,   0 stopped,   0 zombie
Cpu(s):  6.8%us,  1.8%sy,  0.0%ni, 91.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.4%st
Mem:   1758000k total,   582636k used,  1175364k free,   103932k buffers
Swap:   917500k total,        0k used,   917500k free,   180868k cached

procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 0  0      0 1182524 103784 180860    0    0     1     9    6   53  7  2 91  0  0
 0  0      0 1182524 103784 180860    0    0     0    36   70  117  0  0 100  0  0
 0  0      0 1182516 103784 180860    0    0     0     0   73  132  0  1 100  0  0
 0  0      0 1182516 103784 180860    0    0     0     0   60  127  0  0 100  0  0
 1  0      0 1182516 103784 180860    0    0     0     0   62  102  0  0 100  0  0
 0  0      0 1182628 103784 180860    0    0     0     0  289  238  1  2 97  0  0
 2  0      0 1152160 103784 180892    0    0     0     8 1481 2371 54 12 34  0  0
 1  0      0 1182192 103784 180860    0    0     0     0  681  834 19  4 78  0  0
 0  0      0 1182200 103784 180860    0    0     0     0   80  147  0  1 100  0  0
 0  0      0 1182200 103784 180860    0    0     0     0   53  107  0  0 100  0  0
 0  0      0 1182208 103788 180856    0    0     0    72   64  123  0  0 100  1  0