1. only show icon for first cpu

2. ipairs didn't work like pairs,
   values after nil can not be printed,
   don't know why.
e.g.
> aa={1, nil, 3, 4}
> for i,v in ipairs(aa) do print(i, "=", v) end
1	=	1
> for i,v in pairs(aa) do print(i, "=", v) end
1	=	1
3	=	3
4	=	4
> for i,v in next,aa,nil do print(i, "=", v) end
1	=	1
3	=	3
4	=	4
>