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| 1 | +# SPDX-License-Identifier: Apache-2.0 |
| 2 | +""" |
| 3 | +a simple demonstration of RLHF with vLLM, inspired by |
| 4 | +the OpenRLHF framework https://github.com/OpenRLHF/OpenRLHF . |
| 5 | +It follows the design that, training processes and inference processes |
| 6 | +are different, and they live on different GPUs. |
| 7 | +Training processes send prompts to inference processes to generate data, |
| 8 | +and also synchronize the weights of the model by broadcasting the weights |
| 9 | +from the training process to the inference process. |
| 10 | +Note that this is a simple demonstration of one training instance and one |
| 11 | +inference instance. In practice, there could be multiple training instances |
| 12 | +and multiple inference instances. For the full implementation, please refer |
| 13 | +to the OpenRLHF framework. |
| 14 | +""" |
| 15 | +import os |
| 16 | + |
| 17 | +import ray |
| 18 | +import torch |
| 19 | +from ray.util.placement_group import placement_group |
| 20 | +from ray.util.scheduling_strategies import PlacementGroupSchedulingStrategy |
| 21 | +from transformers import AutoModelForCausalLM |
| 22 | + |
| 23 | +from tensorrt_llm import LLM |
| 24 | + |
| 25 | + |
| 26 | +class RayLLM: |
| 27 | + def __init__(self, *args, **kwargs): |
| 28 | + import torch |
| 29 | + dev_count = torch.cuda.device_count() |
| 30 | + print("dev_count: ", dev_count) |
| 31 | + self.mpi_session = None |
| 32 | + for i in range(dev_count): |
| 33 | + device = torch.cuda.get_device_properties(i) |
| 34 | + print(f"pid: {os.getpid()}, device {i}: {device.name}, UUID: {device.uuid}, Memory: {device.total_memory / 1024**2:.0f}MB") |
| 35 | + self.llm = LLM(*args, **kwargs) |
| 36 | + |
| 37 | + def generate(self, prompts): |
| 38 | + ret = [] |
| 39 | + |
| 40 | + llm_ret = self.llm.generate(prompts) |
| 41 | + for r in llm_ret: |
| 42 | + ret.append(r.outputs[0].text) |
| 43 | + |
| 44 | + return ret |
| 45 | + |
| 46 | +""" |
| 47 | +Start the training process, here we use huggingface transformers |
| 48 | +as an example to hold a model on GPU 0. |
| 49 | +""" |
| 50 | + |
| 51 | + |
| 52 | +""" |
| 53 | +Start the inference process, here we use vLLM to hold a model on GPU 1 and |
| 54 | +GPU 2. For the details on how to use ray, please refer to the ray |
| 55 | +documentation https://docs.ray.io/en/latest/ . |
| 56 | +""" |
| 57 | +#os.environ["CUDA_VISIBLE_DEVICES"] = "0,1" |
| 58 | +ray.init(include_dashboard=False) |
| 59 | + |
| 60 | +pg_inference = placement_group([{"GPU": 2, "CPU": 0}]) |
| 61 | +ray.get(pg_inference.ready()) |
| 62 | +scheduling_inference = PlacementGroupSchedulingStrategy( |
| 63 | + placement_group=pg_inference, |
| 64 | + placement_group_capture_child_tasks=True, |
| 65 | + placement_group_bundle_index=0, |
| 66 | +) |
| 67 | +""" |
| 68 | +launch the vLLM inference engine. |
| 69 | +here we use `enforce_eager` to reduce the start time. |
| 70 | +""" |
| 71 | +llm = ray.remote( |
| 72 | + num_cpus=0, |
| 73 | + num_gpus=2, |
| 74 | + scheduling_strategy=scheduling_inference, |
| 75 | +)(RayLLM).remote( |
| 76 | + model='TinyLlama/TinyLlama-1.1B-Chat-v1.0', |
| 77 | + tensor_parallel_size=2, |
| 78 | + # enforce_eager=True, |
| 79 | + # worker_extension_cls="rlhf_utils.WorkerExtension", |
| 80 | + # tensor_parallel_size=2, |
| 81 | + # distributed_executor_backend="ray", |
| 82 | +) |
| 83 | + |
| 84 | +# Generate texts from the prompts. |
| 85 | +prompts = [ |
| 86 | + "Hello, my name is", |
| 87 | + "The president of the United States is", |
| 88 | + "The capital of France is", |
| 89 | + "The future of AI is", |
| 90 | +] |
| 91 | + |
| 92 | +#sampling_params = SamplingParams(temperature=0) |
| 93 | + |
| 94 | +outputs = ray.get(llm.generate.remote(prompts)) |
| 95 | + |
| 96 | +for prompt, output in zip(prompts, outputs): |
| 97 | + print(f"Prompt: {prompt!r}, " |
| 98 | + f"Generated text: {output!r}") |
| 99 | + |
| 100 | +# set up the communication between the training process |
| 101 | +# and the inference engine. |
| 102 | +# master_address = get_ip() |
| 103 | +# master_port = get_open_port() |
| 104 | + |
| 105 | +# handle = llm.collective_rpc.remote("init_weight_update_group", |
| 106 | +# args=('master_address', 5, 0, 3)) |
| 107 | + |
| 108 | +# # model_update_group = stateless_init_process_group(master_address, master_port, |
| 109 | +# # 0, 3, torch.device("cuda:0")) |
| 110 | +# # ray.get(handle) |
| 111 | + |
| 112 | +# # simulate training, modify the weights of the model. |
| 113 | +# # for name, p in train_model.named_parameters(): |
| 114 | +# # p.data.zero_() |
| 115 | + |
| 116 | +# # # sync weight from the training process to the inference engine. |
| 117 | +# # for name, p in train_model.named_parameters(): |
| 118 | +# # handle = llm.collective_rpc.remote("update_weight", |
| 119 | +# # args=(name, p.dtype, p.shape)) |
| 120 | +# # model_update_group.broadcast(p, src=0, stream=torch.cuda.current_stream()) |
| 121 | +# # ray.get(handle) |
| 122 | + |
| 123 | +# # check if the weights are updated. |
| 124 | +# # assert all(ray.get(llm.collective_rpc.remote("check_weights_changed"))) |
| 125 | + |
| 126 | +# # use the updated model to generate texts, they will be nonsense |
| 127 | +# # because the weights are all zeros. |
| 128 | +# outputs_updated = ray.get(llm.generate.remote(prompts, sampling_params)) |
| 129 | +# for output in outputs_updated: |
| 130 | +# prompt = output.prompt |
| 131 | +# generated_text = output.outputs[0].text |
| 132 | +# print(f"Prompt: {prompt!r}, " |
| 133 | +# f"Generated text: {generated_text!r}") |
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