[Fix][MetaSchedule] RPCRunner timeout when queueing up

This PR fixes the timeout rule of MetaSchedule RPCRunner.

Prior to this PR, the RPCRunner sets a timeout threshold for jobs
submitted to popen pool. As a result, the jobs are timed since the
time that they are sent to the remote side.

Consider the case where there is only a single device for measurement.
In this case, all jobs can only be executed serially and jobs must
queue up. Therefore, the previous timeout configuration means the
time spent on queueing will also be counted. This causes some jobs,
in the worst cases, gets timeout without even started to execute,
and has negative impacts on RPC MetaSchedule tuning, from the
perspectives of both efficiency and result performance.

Co-authored-by: Bohan Hou <[email protected]>

python/tvm/meta_schedule/runner/rpc_runner.py

@@ -289,7 +289,6 @@ def __init__(
         logger.info("RPCRunner: max_workers = %d", max_workers)
         self.pool = PopenPoolExecutor(
             max_workers=max_workers,
-            timeout=rpc_config.session_timeout_sec,
             initializer=initializer,
         )
         self._sanity_check()