Update worker.py for compatibility with upstream TVM (#275)

This commit updates `mlc_llm.cli.worker` to be compatible with
upstream TVM apache/tvm#17180, which adds a
`num_groups` argument to the disco worker function.

To de-couple this compatibility from a general TVM version bump, this
commit has a check on the number of `worker.py` arguments provided, to
determine whether the `num_groups` argument is present.  After the TVM
version used by MLC-LLM is updated to include the upstream changes,
this check can be removed.

Author: Lunderberg

python/mlc_llm/cli/worker.py

@@ -16,6 +16,7 @@
 # under the License.
 # pylint: disable=invalid-name
 """Internal DiscoWorker for Disco ProcessSession."""
+
 import os
 import sys
 
@@ -31,23 +32,40 @@
 
 def main():
     """Main worker function"""
-    if len(sys.argv) != 5:
-        print("Usage: <worker_id> <num_workers> <read_fd> <write_fd>")
+
+    if len(sys.argv) == 5 or len(sys.argv) == 6:
+        *args, read_fd, write_fd = map(int, sys.argv[1:])
+    else:
+        print(
+            f"Expected exactly either 4 or 5 arguments, "
+            f"but received {len(sys.argv)-1} arguments.: {sys.argv}"
+        )
+        # The <num_groups> argument was added in
+        # https://github.com/apache/tvm/pull/17180.  This script
+        # currently checks the number of arguments present, to
+        # determine whether `num_groups` was provided.  This allows
+        # the worker.py script provided by MLC-LLM to be compatible
+        # with either pre-17180 or post-17180 arguments.
+        #
+        # After the TVM version used by MLC-LLM includes #17180, the
+        # usage can be updated to always require `len(sys.argv)==6`.
+        print("Usage (without num groups): <worker_id> <num_workers> <read_fd> <write_fd>")
+        print(
+            "Usage (with num groups): <worker_id> <num_workers> <num_groups> <read_fd> <write_fd>"
+        )
         return
 
-    worker_id = int(sys.argv[1])
-    num_workers = int(sys.argv[2])
     if sys.platform == "win32":
         import msvcrt  # pylint: disable=import-outside-toplevel,import-error
 
-        reader = msvcrt.open_osfhandle(int(sys.argv[3]), os.O_BINARY)
-        writer = msvcrt.open_osfhandle(int(sys.argv[4]), os.O_BINARY)
+        reader = msvcrt.open_osfhandle(read_fd, os.O_BINARY)
+        writer = msvcrt.open_osfhandle(write_fd, os.O_BINARY)
     else:
-        reader = int(sys.argv[3])
-        writer = int(sys.argv[4])
+        reader = read_fd
+        writer = write_fd
 
     worker_func = get_global_func("runtime.disco.WorkerProcess")
-    worker_func(worker_id, num_workers, reader, writer)
+    worker_func(*args, reader, writer)
 
 
 if __name__ == "__main__":