Small cleanup. (#1560)

Using a single `os.getenv` statement instead of multiple.
Should make truthful values easier to catch

In the end didn't move towards full CLI because modifying globals in
Python is error prone (depends on code import order).

Added an error when mamba is launched with TP.


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server/text_generation_server/models/flash_causal_lm.py

@@ -28,7 +28,7 @@ from text_generation_server.models.cache_manager import (
     BLOCK_SIZE,
 )
 from text_generation_server.pb import generate_pb2
-from text_generation_server.models.globals import MEM_POOL
+from text_generation_server.models.globals import MEM_POOL, ENABLE_CUDA_GRAPHS
 from text_generation_server.utils import StoppingCriteria, HeterogeneousNextTokenChooser
 from text_generation_server.utils.dist import MEMORY_FRACTION
 
@@ -793,7 +793,7 @@ class FlashCausalLM(Model):
             self.device,
         )
 
-        if os.getenv("ENABLE_CUDA_GRAPHS", "False") == "True":
+        if ENABLE_CUDA_GRAPHS:
             try:
                 logger.info("Experimental support for Cuda Graphs is enabled")
                 # Warmup cuda graphs

server/text_generation_server/models/globals.py

@@ -1,3 +1,6 @@
 import torch
+import os
 
 MEM_POOL = torch.cuda.graph_pool_handle()
+# This is overridden by the cli
+ENABLE_CUDA_GRAPHS = os.getenv("ENABLE_CUDA_GRAPHS", "false").lower() in {"1", "true"}

server/text_generation_server/models/mamba.py

@@ -13,7 +13,7 @@ from text_generation_server.utils import (
     weight_files,
     Weights,
 )
-from text_generation_server.models.globals import MEM_POOL
+from text_generation_server.models.globals import ENABLE_CUDA_GRAPHS, MEM_POOL
 import time
 from text_generation_server.models.custom_modeling.mamba_modeling import MambaModel, InferenceParams
 from text_generation_server.models import Model
@@ -377,7 +377,9 @@ class Mamba(Model):
         dtype: Optional[torch.dtype] = None,
         trust_remote_code: bool = False,
     ):
-        self.process_group, _rank, _world_size = initialize_torch_distributed()
+        self.process_group, _rank, world_size = initialize_torch_distributed()
+        if world_size > 1:
+            raise RuntimeError("Mamba does not support Tensor Parallelism (TP)")
         self.cuda_graphs = {}
         if torch.cuda.is_available():
             device = torch.device("cuda")
@@ -427,7 +429,7 @@ class Mamba(Model):
 
     def warmup(self, batch) -> Optional[int]:
         # TODO: implement warmup for Mamba if needed
-        if os.getenv("ENABLE_CUDA_GRAPHS", "False") == "True":
+        if ENABLE_CUDA_GRAPHS:
             if self.speculate is None or self.speculate == 0:
                 try:
                     logger.info("Experimental support for Cuda Graphs is enabled")