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Nvidia Triton

Dec 20, 20243 min read

Model serving framework optimised for GPU and CPU environments.

Editing pbtxt

PBTXT is the protobuf text format. There is a vscode extension that can be used to provide syntax highlighting:

Name: Protobuf Text Format
Id: thesofakillers.vscode-pbtxt
Description: Protocol Buffer Text Format syntax highlighting for VS Code
Version: 0.0.4
Publisher: thesofakillers
VS Marketplace Link: https://marketplace.visualstudio.com/items?itemName=thesofakillers.vscode-pbtxt

Instance Counts and GPU/CPU

We can set the number of instances of a model that we want to run:

 
instance_group [
{
    count: 1
    kind: KIND_CPU
}
]

Reference: https://docs.nvidia.com/deeplearning/triton-inference-server/user-guide/docs/user_guide/model_configuration.html#cpu-model-instance

Optimization

For CPU execution we can enable OpenVINO acceleration

optimization { execution_accelerators {
  cpu_execution_accelerator : [ {
    name : "openvino"
  } ]
}}

Metrics

By default triton runs its prometheus metrics endpoint on port 8002 so you can do http://hostname:8002/metrics.

Triton Ensemble

In Triton an Ensemble doesn’t mean the same as an Ensemble Model. It is more akin to a classification pipeline

Building an Ensemble

FROM nvcr.io/nvidia/tritonserver:24.01-py3
 
RUN pip3 install transformers
  • docker build -t custom_triton .

Client-Side

Calling a Triton Model with Text

Reference: https://stackoverflow.com/questions/72101578/using-string-parameter-for-nvidia-triton

The key seems to be to tell numpy that the data is an np.object_:

 
import numpy as np
 
input_text = "We are a medical company that specialises in helping with prosthetic legs"
sector_labels = ['Healthcare', 'Software Hardware', 'Professional Services', 'Industry and Manufacturing']
 
input_array = np.array([input_text], dtype=np.object_)
labels = np.array([sector_labels], dtype=np.object_)

Then we pass the type of Bytes to th InferInput object for the dtype:

input = httpclient.InferInput("TEXT", input_array.shape, 'BYTES')
input.set_data_from_numpy(input_array)
 
lbl = httpclient.InferInput("LABELS", labels.shape, 'BYTES')
lbl.set_data_from_numpy(labels)
 
r = client.infer("ensemble_model", inputs=[input, lbl])

Making Requests Over HTTPS and SSL Issues

Started getting errors saying:

ssl EOF in violation of protocol

This is an issue with the underlying HTTP client

pip install --upgrade geventhttpclient

Self-Signed Certificates

ssl and python

Adding Authentication to Triton Client

Use the BasicAuth plugin, pass in credentials

import tritonclient.http as httpclient
from tritonclient._auth import BasicAuth
from tritonclient.utils import InferenceServerException
 
auth_plugin = BasicAuth("<username>","<password>")
client = httpclient.InferenceServerClient('<url>', ssl=True)
client.register_plugin(auth_plugin)

Server-Side

Making Requests to Other Models Within Triton Python Model

We can batch up data and make requests to other models:

requests = []
for i in range(0, len(query_inputs), 4):
    batch_inputs = query_inputs[i:i+4]
    batch_labels = labels[i:i+4]
 
    # Tokenize the batch
    tokens: Dict[str, np.ndarray] = self.tokenizer(
            batch_inputs, batch_labels, return_tensors=TensorType.NUMPY, padding=True
    )   
 
    
    inputs = []
    for input_name in self.tokenizer.model_input_names:
        tensor_input = pb_utils.Tensor(input_name, tokens[input_name])
        inputs.append(tensor_input)
 
    inference_request = pb_utils.InferenceRequest(model_name='deberta',
                        correlation_id=i,
                        inputs=inputs,
                        requested_output_names=['logits'],
                        preferred_memory = pb_utils.PreferredMemory(pb_utils.TRITONSERVER_MEMORY_CPU,0)).async_exec()
 
    requests.append( inference_request )
 
inf_responses = await asyncio.gather(*requests)

the pb_utils.PreferredMemory argument is used to ensure that the resulting tensor is on CPU and can be copied via the get_output_tensor_by_name.

pb_utils and InferenceResponse objects

Getting Data out of Response:

  for response in inf_responses:
      if response.has_error():
          e = response.error()
          print("Error", e.code(), e.message(), flush=True)
          raise Exception(e.message())
          
      print("Response", response, dir(response), flush=True)
 
      print("output dir", dir(response.output_tensors()))
 
      tensor_cpu = pb_utils.get_output_tensor_by_name(response, 'logits')
  
      outputs.append(tensor_cpu.as_numpy())

Model Stats

/v2/models/deberta/versions/1/stats provides model call statistics which are documented here

Graph View

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