Setting number of mappers according to number of TextInput lines

[Ondřej Klimpera]

Hello,

I have very small input size (kB), but processing to produce some output 
takes several minutes. Is there a way how to say, file has 100 lines, i 
need 10 mappers, where each mapper node has to process 10 lines of input 
file?

Thanks for advice.
Ondrej Klimpera