Clarify FP8-Marlin use on capability 8.9 (#2940)

The log message stated that the GPU does not support FP8 on capability
8.9. However we use FP8-Marlin on that capability because it is faster.

server/text_generation_server/layers/fp8.py

@@ -52,6 +52,16 @@ def get_fp8_linear(force_w8a16: bool = False) -> Type[torch.nn.Module]:
             #       gives better decoding throughput on L4 and L40.
             from text_generation_server.layers.marlin import GPTQMarlinFP8Linear
 
+            if major == 8 and minor == 9:
+                log_once(
+                    logger.info,
+                    "GPU supports FP8, but using Marlin FP8 kernel for better performance",
+                )
+            else:
+                log_once(
+                    logger.info, "GPU does not support FP8, using Marlin FP8 kernel"
+                )
+
             return GPTQMarlinFP8Linear
 
     # On other systems let Torch decide if the hardware supports FP8.

server/text_generation_server/layers/marlin/fp8.py

@@ -2,14 +2,12 @@ from typing import Optional
 
 import torch
 import torch.nn as nn
-from loguru import logger
 from text_generation_server.layers.fp8 import fp8_quantize
 from text_generation_server.layers.marlin.gptq import _check_valid_shape
 from text_generation_server.layers.marlin.util import (
     _check_marlin_kernels,
     permute_scales,
 )
-from text_generation_server.utils.log import log_once
 
 try:
     import marlin_kernels
@@ -36,8 +34,6 @@ class GPTQMarlinFP8Linear(nn.Module):
         _check_marlin_kernels()
         assert marlin_kernels is not None
 
-        log_once(logger.info, "GPU does not support FP8, using Marlin FP8 kernel")
-
         scales = scales.unsqueeze(0)
         if scales.shape[1] == 1:
             out_features, in_features = qweight.shape