Data Parallelism Pipeline

Learn how to build a scalable inference pipeline using data parallelism.

In this tutorial, we’ll build a scalable inference data parallelism pipeline for breast cancer detection using data parallelism.

Before You Start #

You must have a Pachyderm cluster up and running
You should have some basic familiarity with Pachyderm pipeline specs – see the Transform, Cross Input, Resource Limits, Resource Requests, and Parallelism sections in particular

Tutorial #

Our Docker image’s user code for this tutorial is built on top of the pytorch/pytorch base image, which includes necessary dependencies. The underlying code and pre-trained breast cancer detection model comes from this repo, developed by the Center of Data Science and Department of Radiology at NYU. Their original paper can be found here.

1. Create a Project & Input Repos #

Create a project named data-parallelism-tutorial.

pachctl create project data-parallelism-tutorial

Set the project as current.

pachctl config update context --project data-parallelism-tutorial

Create the following repos:

pachctl create repo models
pachctl create repo sample_data

2. Create a Classification Pipeline #

We’re going to need to first build a pipeline that will classify the breast cancer images. We’ll use a cross input to combine the sample data and models.

Create a file named bc_classification.json with the following contents:

Resource:

 {
  "pipeline": {
    "name": "bc_classification"
  },
  "description": "Run breast cancer classification.",
  "input": {
    "cross": [
      {
        "pfs": {
          "repo": "sample_data",
          "glob": "/*"
        }
      },
      {
        "pfs": {
          "repo": "models",
          "glob": "/"
        }
      }
    ]
  },
  "transform": {
    "cmd": [
      "/bin/bash", "run.sh", "gpu"
    ],
    "image": "pachyderm/breast_cancer_classifier:1.11.6"
  },
  "resource_limits": {
    "gpu": {
      "type": "nvidia.com/gpu",
      "number": 1
    }
  },
  "resource_requests": {
    "memory": "4G",
    "cpu": 1
  },
  "parallelism_spec": {
    "constant": 8
  }
}

{
 "pipeline": {
     "name": "bc_classification_cpu"
 },
 "description": "Run breast cancer classification.",
 "input": {
     "cross": [
         {
           "pfs": {
             "repo": "sample_data",
             "glob": "/*"
           }
         },
         {
           "pfs": {
             "repo": "models",
             "glob": "/"
           }
         }
       ]
 },
 "transform": {
     "cmd": [
         "/bin/bash",
         "run.sh", "cpu"
     ],
     "image": "pachyderm/breast_cancer_classifier:1.11.6"
 },
 "parallelism_spec": {
   "constant": 4
 }
}

Save the file.

Create the pipeline.

pachctl create pipeline -f /path/to/bc_classification.json

💡

Datum Shape #

When you define a glob pattern in your pipeline, you are defining how Pachyderm should split the data so that the code can execute as parallel jobs without having to modify the underlying implementation.

In this case, we are treating each exam (4 images and a list file) as a single datum. Each datum is processed individually, allowing parallelized computation for each exam that is added. The file structure for our sample_data is organized as follows:

sample_data/
├── <unique_exam_id>
│   ├── L_CC.png
│   ├── L_MLO.png
│   ├── R_CC.png
│   ├── R_MLO.png
│   └── gen_exam_list_before_cropping.pkl
├── <unique_exam_id>
│   ├── L_CC.png
│   ├── L_MLO.png
│   ├── R_CC.png
│   ├── R_MLO.png
│   └── gen_exam_list_before_cropping.pkl
...

The gen_exam_list_before_cropping.pkl is a pickled version of the image list, a requirement of the underlying library being used.

3. Upload Dataset #

Open or download this github repo.
```
gh repo clone pachyderm/docs-content
```

Navigate to this tutorial.

cd content/2.7.x/build-dags/tutorials/data-parallelism

Upload the sample_data and models folders to your repos.

pachctl put file -r sample_data@master -f sample_data/
pachctl put file -r models@master -f models/

User Code Assets #

The Docker image used in this tutorial was built with the following assets:

Assets:

FROM pytorch/pytorch:1.7.1-cuda11.0-cudnn8-devel

# Update NVIDIA's apt-key
# Announcement: https://forums.developer.nvidia.com/t/notice-cuda-linux-repository-key-rotation/212772
ENV DISTRO ubuntu1804
ENV CPU_ARCH x86_64
RUN apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/cuda/repos/$DISTRO/$CPU_ARCH/3bf863cc.pub

RUN apt-get update && apt-get install -y git libgl1-mesa-glx libglib2.0-0

WORKDIR /workspace
RUN git clone https://github.com/jimmywhitaker/breast_cancer_classifier.git /workspace
RUN pip install --upgrade pip && pip install -r requirements.txt
RUN pip install matplotlib --ignore-installed

RUN apt-get -y install tree

COPY . /workspace

 #!/bin/bash

NUM_PROCESSES=10
DEVICE_TYPE=$1
NUM_EPOCHS=10
HEATMAP_BATCH_SIZE=100
GPU_NUMBER=0

ID=$(ls /pfs/sample_data/ | head -n 1)
DATA_FOLDER="/pfs/sample_data/${ID}/"
INITIAL_EXAM_LIST_PATH="/pfs/sample_data/${ID}/gen_exam_list_before_cropping.pkl"
PATCH_MODEL_PATH="/pfs/models/sample_patch_model.p"
IMAGE_MODEL_PATH="/pfs/models/sample_image_model.p"
IMAGEHEATMAPS_MODEL_PATH="/pfs/models/sample_imageheatmaps_model.p"

CROPPED_IMAGE_PATH="/pfs/out/${ID}/cropped_images"
CROPPED_EXAM_LIST_PATH="/pfs/out/${ID}/cropped_images/cropped_exam_list.pkl"
EXAM_LIST_PATH="/pfs/out/${ID}/data.pkl"
HEATMAPS_PATH="/pfs/out/${ID}/heatmaps"
IMAGE_PREDICTIONS_PATH="/pfs/out/${ID}/image_predictions.csv"
IMAGEHEATMAPS_PREDICTIONS_PATH="/pfs/out/${ID}/imageheatmaps_predictions.csv"
export PYTHONPATH=$(pwd):$PYTHONPATH

echo 'Stage 1: Crop Mammograms'
python3 src/cropping/crop_mammogram.py \
    --input-data-folder $DATA_FOLDER \
    --output-data-folder $CROPPED_IMAGE_PATH \
    --exam-list-path $INITIAL_EXAM_LIST_PATH  \
    --cropped-exam-list-path $CROPPED_EXAM_LIST_PATH  \
    --num-processes $NUM_PROCESSES

echo 'Stage 2: Extract Centers'
python3 src/optimal_centers/get_optimal_centers.py \
    --cropped-exam-list-path $CROPPED_EXAM_LIST_PATH \
    --data-prefix $CROPPED_IMAGE_PATH \
    --output-exam-list-path $EXAM_LIST_PATH \
    --num-processes $NUM_PROCESSES

echo 'Stage 3: Generate Heatmaps'
python3 src/heatmaps/run_producer.py \
    --model-path $PATCH_MODEL_PATH \
    --data-path $EXAM_LIST_PATH \
    --image-path $CROPPED_IMAGE_PATH \
    --batch-size $HEATMAP_BATCH_SIZE \
    --output-heatmap-path $HEATMAPS_PATH \
    --device-type $DEVICE_TYPE \
    --gpu-number $GPU_NUMBER

echo 'Stage 4a: Run Classifier (Image)'
python3 src/modeling/run_model.py \
    --model-path $IMAGE_MODEL_PATH \
    --data-path $EXAM_LIST_PATH \
    --image-path $CROPPED_IMAGE_PATH \
    --output-path $IMAGE_PREDICTIONS_PATH \
    --use-augmentation \
    --num-epochs $NUM_EPOCHS \
    --device-type $DEVICE_TYPE \
    --gpu-number $GPU_NUMBER

echo 'Stage 4b: Run Classifier (Image+Heatmaps)'
python3 src/modeling/run_model.py \
    --model-path $IMAGEHEATMAPS_MODEL_PATH \
    --data-path $EXAM_LIST_PATH \
    --image-path $CROPPED_IMAGE_PATH \
    --output-path $IMAGEHEATMAPS_PREDICTIONS_PATH \
    --use-heatmaps \
    --heatmaps-path $HEATMAPS_PATH \
    --use-augmentation \
    --num-epochs $NUM_EPOCHS \
    --device-type $DEVICE_TYPE \
    --gpu-number $GPU_NUMBER