Strategize slicing based on free [V]RAM (#2572)

Strategize slicing based on free [V]RAM when not using xformers. Free [V]RAM is evaluated at every generation. When there's enough memory, the entire generation occurs without slicing. If there is not enough free memory, we use diffusers' sliced attention.

ldm/generate.py

@@ -223,7 +223,7 @@ class Generate:
         self.model_name  = model or fallback
 
         # for VRAM usage statistics
-        self.session_peakmem = torch.cuda.max_memory_allocated() if self._has_cuda else None
+        self.session_peakmem = torch.cuda.max_memory_allocated(self.device) if self._has_cuda else None
         transformers.logging.set_verbosity_error()
 
         # gets rid of annoying messages about random seed
@@ -592,20 +592,24 @@ class Generate:
         self.print_cuda_stats()
         return results
 
-    def clear_cuda_cache(self):
+    def gather_cuda_stats(self):
         if self._has_cuda():
             self.max_memory_allocated = max(
                 self.max_memory_allocated,
-                torch.cuda.max_memory_allocated()
+                torch.cuda.max_memory_allocated(self.device)
             )
             self.memory_allocated = max(
                 self.memory_allocated,
-                torch.cuda.memory_allocated()
+                torch.cuda.memory_allocated(self.device)
             )
             self.session_peakmem = max(
                 self.session_peakmem,
-                torch.cuda.max_memory_allocated()
+                torch.cuda.max_memory_allocated(self.device)
             )
+
+    def clear_cuda_cache(self):
+        if self._has_cuda():
+            self.gather_cuda_stats()
             torch.cuda.empty_cache()
 
     def clear_cuda_stats(self):
@@ -614,6 +618,7 @@ class Generate:
 
     def print_cuda_stats(self):
         if self._has_cuda():
+            self.gather_cuda_stats()
             print(
                 '>>   Max VRAM used for this generation:',
                 '%4.2fG.' % (self.max_memory_allocated / 1e9),

ldm/invoke/generator/diffusers_pipeline.py

@@ -301,10 +301,8 @@ class StableDiffusionGeneratorPipeline(StableDiffusionPipeline):
             textual_inversion_manager=self.textual_inversion_manager
         )
 
-        self._enable_memory_efficient_attention()
 
-
+    def _adjust_memory_efficient_attention(self, latents: Torch.tensor):
-    def _enable_memory_efficient_attention(self):
         """
         if xformers is available, use it, otherwise use sliced attention.
         """
@@ -317,7 +315,24 @@ class StableDiffusionGeneratorPipeline(StableDiffusionPipeline):
                 # fix is in https://github.com/kulinseth/pytorch/pull/222 but no idea when it will get merged to pytorch mainline.
                 pass
             else:
-                self.enable_attention_slicing(slice_size='max')
+                if self.device.type == 'cpu' or self.device.type == 'mps':
+                    mem_free = psutil.virtual_memory().free
+                elif self.device.type == 'cuda':
+                    mem_free, _ = torch.cuda.mem_get_info(self.device)
+                else:
+                    raise ValueError(f"unrecognized device {device}")
+                # input tensor of [1, 4, h/8, w/8]
+                # output tensor of [16, (h/8 * w/8), (h/8 * w/8)]
+                bytes_per_element_needed_for_baddbmm_duplication = latents.element_size() + 4
+                max_size_required_for_baddbmm = \
+                    16 * \
+                    latents.size(dim=2) * latents.size(dim=3) * latents.size(dim=2) * latents.size(dim=3) * \
+                    bytes_per_element_needed_for_baddbmm_duplication
+                if max_size_required_for_baddbmm > (mem_free * 3.3 / 4.0): # 3.3 / 4.0 is from old Invoke code
+                    self.enable_attention_slicing(slice_size='max')
+                else:
+                    self.disable_attention_slicing()
+
 
     def image_from_embeddings(self, latents: torch.Tensor, num_inference_steps: int,
                               conditioning_data: ConditioningData,
@@ -377,6 +392,7 @@ class StableDiffusionGeneratorPipeline(StableDiffusionPipeline):
                                          noise: torch.Tensor,
                                          run_id: str = None,
                                          additional_guidance: List[Callable] = None):
+        self._adjust_memory_efficient_attention(latents)
         if run_id is None:
             run_id = secrets.token_urlsafe(self.ID_LENGTH)
         if additional_guidance is None: