slow directory operation on huge dirs

[Wojciech Puchar]

>>> 
>> nobody have idea what's the problem?
>
> Is it "just slow" or is your disk too busy? (iostat)

no. disk is idle, system CPU load takes half of system (8 cores)!

>
> Can it be that pre-cacheing on huge directory makes disk too busy because 
> there is too much to read?
this part works fine. The problem begins where it's already cached.

To get the problem you need BOTH of:

- large maxvnodes like half million
- large directory (in order of 100000 files)