From f3393633e4230c84dfe260cd739c4cb83a1d1057 Mon Sep 17 00:00:00 2001
From: Howard Huang <howardhuang96@gmail.com>
Date: Thu, 15 Aug 2024 23:30:41 -0400
Subject: [PATCH] Fail when using tracer made without seed checkpoint (#522)

Stack from [ghstack](https://github.com/ezyang/ghstack) (oldest at
bottom):
* #473
* __->__ #522
---
 train.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/train.py b/train.py
index d297b8a7..a6bcbdd8 100644
--- a/train.py
+++ b/train.py
@@ -204,6 +204,11 @@ def loss_fn(pred, labels):
     checkpoint_loaded = checkpoint.load()
 
     if parallel_dims.pp_enabled and not checkpoint_loaded:
+        if job_config.experimental.pipeline_parallel_split_mode == "tracer":
+            raise RuntimeError(
+                "Pipeline parallelism with tracer mode is not supported without a seed checkpoint."
+            )
+
         # TODO: fix this by allowing each rank to set their own seed
         logger.warning(
             "Pipeline Parallelism is being used without a seed checkpoint. "