[inductor] Copy RedisRemoteCacheBackend into pytorch (#127480)

Summary: We need an implementation of RedisRemoteCacheBackend with the same API that we're using for FbMemcacheRemoteFxGraphCacheBackend. So we'll stop using the Triton implementation and adapt a version for use by inductor. I also renamed parameters and cache entries to match our cache terminology.

Test Plan: Ran this command twice and inspected log output to ensure I got cache hits:
```
TORCH_LOGS=+torch._inductor.codecache TORCHINDUCTOR_FX_GRAPH_REMOTE_CACHE=1 python benchmarks/dynamo/torchbench.py --performance --inductor --device cuda --training --amp --print-compilation-time --only dcgan
```

Pull Request resolved: https://github.com/pytorch/pytorch/pull/127480
Approved by: https://github.com/oulgen

mypy.ini

@@ -294,3 +294,10 @@ ignore_missing_imports = True
 
 [mypy-torch_xla.*]
 ignore_missing_imports = True
+
+#
+# Third party dependencies that are optional.
+#
+
+[mypy-redis]
+ignore_missing_imports = True

test/inductor/test_codecache.py

@@ -197,7 +197,7 @@ class TestFxGraphCache(TestCase):
         cache_module = (
             "triton.runtime.fb_memcache.FbMemcacheRemoteFxGraphCacheBackend"
             if config.is_fbcode()
-            else "triton.runtime.cache.RedisRemoteCacheBackend"
+            else "torch._inductor.remote_cache.RedisRemoteCacheBackend"
         )
 
         with config.patch(

test/inductor/test_max_autotune.py

@@ -269,7 +269,7 @@ class TestMaxAutotune(TestCase):
         cache_module = (
             "triton.runtime.fb_memcache.FbMemcacheRemoteAutotuneCacheBackend"
             if config.is_fbcode()
-            else "triton.runtime.cache.RedisRemoteCacheBackend"
+            else "torch._inductor.remote_cache.RedisRemoteCacheBackend"
         )
 
         with config.patch(

torch/_inductor/codecache.py

@@ -976,16 +976,16 @@ class FxGraphCache:
             if remote:
                 cache_id = "fx-graph-v1"
                 try:
-                    import triton
-
                     if config.is_fbcode():
-                        remote_cache = triton.runtime.fb_memcache.FbMemcacheRemoteFxGraphCacheBackend(
-                            cache_id
+                        from triton.runtime.fb_memcache import (
+                            FbMemcacheRemoteFxGraphCacheBackend,
                         )
+
+                        remote_cache = FbMemcacheRemoteFxGraphCacheBackend(cache_id)
                     else:
-                        remote_cache = triton.runtime.cache.RedisRemoteCacheBackend(
-                            cache_id
-                        )
+                        from torch._inductor.remote_cache import RedisRemoteCacheBackend
+
+                        remote_cache = RedisRemoteCacheBackend(cache_id)
                 except Exception:
                     remote_cache = None
                     log.warning("Unable to create a remote cache", exc_info=True)

torch/_inductor/remote_cache.py

@@ -0,0 +1,46 @@
+import os
+from abc import abstractmethod
+
+
+class RemoteCacheBackend:
+    """
+    A backend implementation for accessing a remote/distributed cache.
+    """
+
+    def __init__(self, cache_id: str):
+        pass
+
+    @abstractmethod
+    def get(self, key: str):
+        pass
+
+    @abstractmethod
+    def put(self, key: str, data: bytes):
+        pass
+
+
+class RedisRemoteCacheBackend(RemoteCacheBackend):
+    """
+    A Redis implementation of a remote/distributed cache.
+    """
+
+    def __init__(self, cache_id: str):
+        import redis
+
+        self._cache_id = cache_id
+        self._key_fmt = os.environ.get(
+            "TORCHINDUCTOR_REDIS_KEY_FORMAT", "pt2:{cache_id}:{key}"
+        )
+        self._redis = redis.Redis(
+            host=os.environ.get("TRITON_REDIS_HOST", "localhost"),
+            port=int(os.environ.get("TRITON_REDIS_PORT", 6379)),
+        )
+
+    def _get_key(self, key: str) -> str:
+        return self._key_fmt.format(cache_id=self._cache_id, key=key)
+
+    def get(self, key: str):
+        return self._redis.get(self._get_key(key))
+
+    def put(self, key: str, data: bytes):
+        return self._redis.set(self._get_key(key), data)

torch/_inductor/runtime/triton_heuristics.py

@@ -1078,7 +1078,9 @@ def cached_autotune(
                             key
                         )
                     else:
-                        remote_cache = triton.runtime.cache.RedisRemoteCacheBackend(key)
+                        from torch._inductor.remote_cache import RedisRemoteCacheBackend
+
+                        remote_cache = RedisRemoteCacheBackend(key)
                 except Exception:
                     remote_cache = None
                     log.warning("Unable to create a remote cache", exc_info=True)