增加多GPU并发支持

apps/rmbg/service.py

@@ -16,6 +16,7 @@ import logging
 from concurrent.futures import ThreadPoolExecutor
 from dataclasses import dataclass
 from typing import Optional, Dict, Any
+from threading import Lock
 from settings import settings
 
 logging.basicConfig(
@@ -43,8 +44,13 @@ class RmbgService:
     def __init__(self, model_path=None):
         """初始化背景移除服务"""
         self.model_path = model_path or settings.model_path
+        # 单机多 GPU：维护模型和设备列表，兼容旧字段
+        self.models = []
+        self.devices = []
         self.model = None
         self.device = None
+        self._gpu_lock = Lock()
+        self._next_gpu_index = 0
         self.save_dir = settings.save_dir
         self.download_url = settings.download_url
         os.makedirs(self.save_dir, exist_ok=True)
@@ -67,53 +73,86 @@ class RmbgService:
         # 队列任务将在 FastAPI startup 事件中启动
         
     def _load_model(self):
-        """加载模型"""
+        """加载模型，支持多 GPU"""
-        self.device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
+        # 优化显存分配策略：减少碎片化（需要在加载前设置）
-        
-        # 优化显存占用：使用半精度加载（如果支持）
-        # 注意：某些模型可能不支持半精度，需要测试
-        try:
-            # 尝试使用半精度加载，可以减少约50%的显存占用
-            self.model = AutoModelForImageSegmentation.from_pretrained(
-                self.model_path, 
-                trust_remote_code=True,
-                torch_dtype=torch.float16 if torch.cuda.is_available() else torch.float32
-            )
-            self.model = self.model.to(self.device)
-            if torch.cuda.is_available():
-                self.model = self.model.half()  # 转换为半精度
-        except Exception as e:
-            # 如果半精度加载失败，降级到全精度
-            logger.warning(f"半精度加载失败，使用全精度: {str(e)}")
-            self.model = AutoModelForImageSegmentation.from_pretrained(
-                self.model_path, 
-                trust_remote_code=True
-            )
-            self.model = self.model.to(self.device)
-        
-        self.model.eval()
-        
-        # 优化显存分配策略：减少碎片化
         if torch.cuda.is_available():
-            # 设置显存分配器，减少碎片化
             os.environ.setdefault('PYTORCH_CUDA_ALLOC_CONF', 'expandable_segments:True')
+        
+        num_gpus = torch.cuda.device_count() if torch.cuda.is_available() else 0
+        use_half = torch.cuda.is_available()
+
+        def _load_single_model(device: torch.device):
+            """在指定 device 上加载一个模型实例"""
+            try:
+                model = AutoModelForImageSegmentation.from_pretrained(
+                    self.model_path,
+                    trust_remote_code=True,
+                    torch_dtype=torch.float16 if use_half else torch.float32,
+                )
+                model = model.to(device)
+                if use_half:
+                    model = model.half()
+            except Exception as e:
+                # 如果半精度加载失败，降级到全精度
+                logger.warning(f"设备 {device} 半精度加载失败，使用全精度: {str(e)}")
+                model = AutoModelForImageSegmentation.from_pretrained(
+                    self.model_path,
+                    trust_remote_code=True,
+                )
+                model = model.to(device)
+            model.eval()
+            return model
+
+        if num_gpus > 0:
+            # 为每张 GPU 加载一份模型，简单轮询调度
+            for idx in range(num_gpus):
+                device = torch.device(f"cuda:{idx}")
+                model = _load_single_model(device)
+                self.devices.append(device)
+                self.models.append(model)
+            logger.info(f"检测到 {num_gpus} 张 GPU，已为每张 GPU 加载模型实例")
+        else:
+            # 仅 CPU
+            device = torch.device("cpu")
+            model = _load_single_model(device)
+            self.devices.append(device)
+            self.models.append(model)
+            logger.info("未检测到 GPU，使用 CPU 设备")
+
+        # 兼容旧字段：默认指向第一个设备和模型
+        self.device = self.devices[0]
+        self.model = self.models[0]
+
+        if torch.cuda.is_available():
             torch.cuda.empty_cache()
 
+    def _get_model_and_device(self):
+        """为一次推理选择一个模型和设备（轮询）"""
+        if not self.models or not self.devices:
+            raise RuntimeError("模型尚未加载")
+        if len(self.models) == 1:
+            return self.models[0], self.devices[0]
+        with self._gpu_lock:
+            idx = self._next_gpu_index
+            self._next_gpu_index = (self._next_gpu_index + 1) % len(self.models)
+        return self.models[idx], self.devices[idx]
+
     def _process_image_sync(self, image):
         """同步处理图像，移除背景（单张）"""
+        model, device = self._get_model_and_device()
         image_size = image.size
         transform_image = transforms.Compose([
             transforms.Resize((1024, 1024)),
             transforms.ToTensor(),
             transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225]),
         ])
-        input_images = transform_image(image).unsqueeze(0).to(self.device)
+        input_images = transform_image(image).unsqueeze(0).to(device)
         # 如果模型是半精度，输入也转换为半精度
-        if next(self.model.parameters()).dtype == torch.float16:
+        if next(model.parameters()).dtype == torch.float16:
             input_images = input_images.half()
         
         with torch.no_grad():
-            preds = self.model(input_images)[-1].sigmoid().cpu()
+            preds = model(input_images)[-1].sigmoid().cpu()
         
         pred = preds[0].squeeze()
         pred_pil = transforms.ToPILImage()(pred)
@@ -132,6 +171,34 @@ class RmbgService:
         if not images_with_info:
             return []
 
+        # 单设备退化为原来的逻辑，多设备时按设备拆分子批次并行执行
+        if len(self.models) == 1:
+            return self._process_batch_on_device(self.models[0], self.devices[0], images_with_info)
+
+        # 简单均匀拆分到各个 GPU，上游调用会按 index 重新排序
+        tasks = []
+        for i, (model, device) in enumerate(zip(self.models, self.devices)):
+            sub_items = images_with_info[i::len(self.models)]
+            if not sub_items:
+                continue
+            tasks.append(
+                self.executor.submit(self._process_batch_on_device, model, device, sub_items)
+            )
+
+        all_results = []
+        for fut in tasks:
+            try:
+                sub_res = fut.result()
+                all_results.extend(sub_res)
+            except Exception as e:
+                logger.error(f"多 GPU 子批次处理失败: {e}", exc_info=True)
+
+        # 保证结果顺序与原始 index 一致
+        all_results.sort(key=lambda x: x[1])
+        return all_results
+
+    def _process_batch_on_device(self, model, device, images_with_info):
+        """在指定 device 上批量处理图像"""
         transform_image = transforms.Compose([
             transforms.Resize((1024, 1024)),
             transforms.ToTensor(),
@@ -142,15 +209,15 @@ class RmbgService:
         for image, image_size, index in images_with_info:
             batch_tensors.append(transform_image(image))
         
-        input_batch = torch.stack(batch_tensors).to(self.device)
+        input_batch = torch.stack(batch_tensors).to(device)
         # 如果模型是半精度，输入也转换为半精度
-        if next(self.model.parameters()).dtype == torch.float16:
+        if next(model.parameters()).dtype == torch.float16:
             input_batch = input_batch.half()
         # 释放 batch_tensors 占用的 CPU 内存
         del batch_tensors
         
         with torch.no_grad():
-            model_output = self.model(input_batch)
+            model_output = model(input_batch)
             if isinstance(model_output, (list, tuple)):
                 preds = model_output[-1].sigmoid().cpu()
             else: