load_test: update the Queue class provider to work well on MacOS (#92)

* load_test: update the Queue class provider to work well on MacOS

see https://stackoverflow.com/questions/65609529/python-multiprocessing-queue-notimplementederror-macos

* load_test: add shebang header

Makes it easier to run the load test. And the executable flag is already set.

load_test.py

@@ -1,3 +1,5 @@
+#! /usr/bin/env python3
+
 """Main llm-load-test CLI entrypoint."""
 
 import logging
@@ -117,12 +119,14 @@ def main(args):
     args = utils.parse_args(args)
 
     mp_ctx = mp.get_context("spawn")
-    logger_q = mp_ctx.Queue()
+    mp_mgr = mp_ctx.Manager()
+
+    logger_q = mp_mgr.Queue()
     log_reader_thread = logging_utils.init_logging(args.log_level, logger_q)
 
     # Create processes and their Users
-    stop_q = mp_ctx.Queue(1)
-    dataset_q = mp_ctx.Queue()
+    stop_q = mp_mgr.Queue(1)
+    dataset_q = mp_mgr.Queue()
     procs = []
     results_pipes = []