FEAT-modin-project#6908: Make it clearer which parameters to pass int…

…o the engine initialization

Signed-off-by: Igoshev, Iaroslav <iaroslav.igoshev@intel.com>

modin/core/execution/dask/common/utils.py

@@ -50,7 +50,7 @@ def _disable_warnings():
             """
     from distributed import Client
 
-    client = Client()
+    client = Client(n_workers=<N1>, threads_per_worker=<N2>)
 """,
         )
         num_cpus = CpuCount.get()
@@ -59,7 +59,11 @@ def _disable_warnings():
 
         # when the client is initialized, environment variables are inherited
         with set_env(PYTHONWARNINGS="ignore::FutureWarning"):
-            client = Client(n_workers=num_cpus, memory_limit=worker_memory_limit)
+            client = Client(
+                n_workers=num_cpus,
+                threads_per_worker=1,
+                memory_limit=worker_memory_limit,
+            )
 
         if GithubCI.get():
             # set these keys to run tests that write to the mock s3 service. this seems

modin/core/execution/ray/common/utils.py

@@ -118,13 +118,21 @@ def initialize_ray(
                 **extra_init_kw,
             )
         else:
+            init_params_str = "num_cpus=<N>"
+            if extra_init_kw:
+                init_params_str = (
+                    init_params_str
+                    + ", "
+                    + ", ".join([f"{k}={v}" for k, v in extra_init_kw.items()])
+                )
             # This string is intentionally formatted this way. We want it indented in
             # the warning message.
             ErrorMessage.not_initialized(
                 "Ray",
                 f"""
     import ray
-    ray.init({', '.join([f'{k}={v}' for k,v in extra_init_kw.items()])})
+
+    ray.init({init_params_str})
 """,
             )
             object_store_memory = _get_object_store_memory()