Revert "limit fused kernel num args. (#113131)"

This reverts commit 7b442c2b0a.

Reverted https://github.com/pytorch/pytorch/pull/113131 on behalf of https://github.com/albanD due to Breaks lint on trunk ([comment](https://github.com/pytorch/pytorch/pull/113131#issuecomment-1817548349))

test/inductor/test_torchinductor.py

@@ -7712,24 +7712,6 @@ class CommonTemplate:
         b = torch.randn(65, 2**24, device=self.device)
         fn(a, b)
 
-    def test_fuse_large_params(self):
-        def pt2_optimizer_step(optimizer):
-            @torch.compile()
-            def f():
-                optimizer.step()
-
-            f()
-
-        params = [
-            torch.rand(10, 10, dtype=torch.float32, device=self.device)
-            for _ in range(194)
-        ]
-        for p in params:
-            p.grad = torch.rand_like(p)
-
-        o = torch.optim.AdamW(params)
-        pt2_optimizer_step(o)
-
     def test_adaptive_avg_pool1d_argmax(self):
         # https://github.com/pytorch/pytorch/issues/113013
         def fn(x):

torch/_inductor/codegen/cpp.py

@@ -2809,18 +2809,9 @@ class CppKernelProxy(CppKernel):
 
 
 class CppScheduling(BaseScheduling):
-    # ctypes limits the number of args to 1024, refer to:
-    # https://github.com/python/cpython/commit/a285af7e626d1b81cf09f8b2bf7656f100bc1237
-    # We set a conservative threshold here.
-    MAX_FUSED_KERNEL_ARGS_NUM = 500
-
     def __init__(self, scheduler):
         self.scheduler = scheduler
         self.get_kernel_group()
-        self._ready_to_flush = False
-
-    def _set_flush_status(self, status: bool):
-        self._ready_to_flush = status
 
     def group_fn(self, sizes):
         return tuple(tuple(map(V.graph.sizevars.simplify, s)) for s in sizes)
@@ -2867,23 +2858,12 @@ class CppScheduling(BaseScheduling):
 
         kernel_group.finalize_kernel(cpp_kernel_proxy, nodes)
 
-        args_num = self._get_scheduled_num_args()
-        if args_num > CppScheduling.MAX_FUSED_KERNEL_ARGS_NUM:
-            self._set_flush_status(True)
-
-    def _get_scheduled_num_args(self):
-        return self.kernel_group.get_num_args()
-
-    def ready_to_flush(self):
-        return self._ready_to_flush
-
     def codegen_sync(self):
         pass
 
     def flush(self):
         self.kernel_group.codegen_define_and_call(V.graph.wrapper_code)
         self.get_kernel_group()
-        self._set_flush_status(False)
 
 
 class KernelGroup:
@@ -2905,11 +2885,6 @@ class KernelGroup:
         ws = self.ws
         new_kernel.codegen_loops(code, ws)
 
-    def get_num_args(self):
-        arg_defs, call_args, arg_types = self.args.cpp_argdefs()
-        args_num = len(arg_defs)
-        return args_num
-
     def codegen_define_and_call(self, wrapper):
         self.stack.close()
         if not self.scheduled_nodes:

torch/_inductor/codegen/triton.py

@@ -2850,9 +2850,6 @@ class TritonScheduling(BaseScheduling):
     def flush(self):
         pass
 
-    def ready_to_flush(self) -> bool:
-        return False
-
     def benchmark_fused_nodes(self, nodes):
         _, (numel, rnumel) = max(nodes, key=lambda x: int(x.is_reduction())).group
         node_schedule = self.generate_node_schedule(nodes, numel, rnumel)

torch/_inductor/scheduler.py

@@ -2134,7 +2134,6 @@ class Scheduler:
     @dynamo_timed
     def codegen(self):
         for node in self.nodes:
-            device = None
             try:
                 log.debug(
                     "Generating code for node %s with estimated runtime %f",
@@ -2190,9 +2189,6 @@ class Scheduler:
 
             self.available_buffer_names.update(node.get_names())
 
-            if device is not None and self.get_backend(device).ready_to_flush():
-                self.flush()
-
         self.flush()
 
     def is_unaligned_buffer(self, buf_name):
@@ -2249,13 +2245,6 @@ class BaseScheduling:
         """
         raise NotImplementedError()
 
-    def ready_to_flush(self) -> bool:
-        """
-        Check whether the backend is request scheduler flush the generated kernel.
-        If not support, please return False.
-        """
-        return False
-
     def flush(self):
         """
         Flush the generated kernel and python wrapper code to the source code file.