Automate benchmarking (#760)

## Summary
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this proposed code change. --->
This PR sets the time limit for the modal to run to 90 minutes and also
the workflow would be triggered every Friday.
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## Details
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should be aware of?
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## Testing Done
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tested. --->

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- Hardware Type: <BLANK>
- [ ] run `make test` to ensure correctness
- [ ] run `make checkstyle` to ensure code style
- [ ] run `make test-convergence` to ensure convergence

---------

Co-authored-by: Manan Shah <[email protected]>
Co-authored-by: Vaibhav Jindal <[email protected]>

.github/workflows/benchmark.yml

@@ -1,13 +1,10 @@
 name: Benchmarks
 
 on:
-  push:
-    branches:
-      - main
-    # paths:
-    #   - "src/**"
-    #   - "test/**"
-    #   - "benchmark/**"
+  schedule:
+    # Runs at 00:00 UTC every Friday
+    - cron: '0 0 * * 5'
+  workflow_dispatch:  # Enables manual trigger
 
 permissions:
   contents: write

dev/modal/benchmarks.py

@@ -14,7 +14,7 @@ app = modal.App("liger_benchmarks", image=image)
 repo = image.add_local_dir(ROOT_PATH, remote_path=REMOTE_ROOT_PATH)
 
 
-@app.function(gpu="H100", image=repo, timeout=60 * 45)
+@app.function(gpu="H100", image=repo, timeout=60 * 90)
 def liger_benchmarks():
     import os
     import subprocess