Combine batch task and Snakemake

[JiahuaQu]

Hi, thank you for introducing Snakemake. I wonder how to combine batch task in HPC and Snakemake. Specifically, we need request the running time and CPU/memory when we submit a task in HPC. The appropriate amount of time and memory we specified can shorten the queue time and accelerate our analysis progress. Although there is the thread parameter in Snakemake,
(1) Is there the maximum running time parameter?
(2) Where to specify the qsub or other submission command to HPC in the Snakemake script? Inside each rule or outside the complete Snakemake script?
(3) Do we have to request the running time and memory outside the Snakemake script when submitting the entire program as a whole?
(3.1) In that way, the requested time should be the sum time of all processes/rules and the requested CPU/memory should be largest CPU/threads needed among the rules/processes.
(3.2) If only one rule/process needs 10 threads/CPUs but others only need 2, the requested CPU as 10 will waste the CPU for running other rules/process in most of the time?

Thank you.