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Skill

udf-benchmark

benchmark Spark UDF performance on GPU

Published by NVIDIA Updated Jul 14
Covers Performance Benchmarking NVIDIA Spark

Description

Assists with benchmarking and profiling the performance of an Apache Spark UDF on the GPU. This is step 3 of 3 in the UDF conversion workflow (udf-gen-test -> udf-convert-to-* -> udf-benchmark). Use this skill when you have a CPU UDF and a RapidsUDF or SQL implementation, and need to benchmark the performance of the CPU UDF against the GPU implementation.

SKILL.md

UDF Benchmark

Workflow

  • Step 1: Implement BenchUtils (fill in TODO methods)
  • Step 2: Validate with a small dataset
  • Step 3: Generate full benchmark data and run benchmarks
  • Step 4: cuDF microbenchmarks (skip for SQL targets)

Before making any edits, create a visible TODO checklist for every workflow step in this skill and keep it updated. Do not produce a final answer until every required checklist item is marked complete.

Prerequisites

  • Project directory from Steps 1-2 (udf-gen-test, udf-convert-to-*) with passing tests

Derive <CamelName> and <snake_name> from the UDF class name.

Note: Commands require access to /tmp (Spark temp storage) and /dev (GPU device). If commands fail due to sandbox restrictions, re-run them unsandboxed.

Step 1: Implement BenchUtils

Read src/main/scala/com/udf/bench/BenchUtils.scala. Replace placeholders with the actual camel/snake UDF name.

Fill in the TODO methods following the docstrings. For variable-length inputs, generate sizable rows representative of enterprise-scale data. Refer to the unit test for schema and example data.

Step 2: Validate

Make scripts executable:

chmod +x *.sh

Run validation mode to test with a small dataset:

./run_gen_data.sh --rows 1000 --validate

This runs both the CPU and GPU implementations on the dataset. If validation fails, analyze the error and fix the BenchUtils implementation.

Step 3: Generate Data and Run Benchmarks

The scripts set the default heap size to 16g in .mvn/jvm.config; adjust depending on data size.

Generate benchmark data (10M rows):

./run_gen_data.sh --rows 10000000

Run benchmarks:

# CPU benchmark
./run_spark_benchmark.sh --mode cpu --data-path data/bench_data_10000000_rows.parquet

# GPU benchmark
./run_spark_benchmark.sh --mode gpu --data-path data/bench_data_10000000_rows.parquet

Results are saved to the results/ directory as JSON files.

Step 4: cuDF Microbenchmarks

Skip this step for SQL targets. This only applies to cuDF RapidsUDF conversions.

Follow CUDF_MICROBENCHMARKS.md to implement and run in-memory microbenchmarks.

Output

Upon successful completion:

  • Benchmark utilities: src/main/scala/com/udf/bench/BenchUtils.scala
  • Microbenchmarks (cuDF): src/main/scala/com/udf/bench/MicroBenchRunner.scala
  • Generated data: data/
  • Benchmark results: results/

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