1.
Stage Level Scheduling
Improving Big Data and
AI integration
Thomas Graves
Software Engineer at NVIDIA
Spark PMC

2.
Agenda
§ Resource Scheduling
§ Stage Level Scheduling
§ Use Case Example
§ Demo

3.
Resource Scheduling On Spark

4.
Resource Scheduling
• Driver
• Cores
• Memory
• Accelerators (GPU/FPGA/etc)
• Executors
• Cores
• Memory (overhead, pyspark, heap, offheap)
• Accelerators (GPU/FPGA/etc)
• Tasks (requirements)
• CPUs
• Accelerators (GPU/FPGA/etc)

5.
Resource Scheduling
• Tasks Per Executor
• Executor Resources / Task Requirements
• Configs
spark.driver.cores=1
spark.executor.cores=4
spark.task.cpus=1
spark.driver.memory=4g
spark.executor.memory=4g
spark.executor.memoryOverhead=2g
spark.driver.resource.gpu.amount=1
spark.driver.resource.gpu.discoveryScript=./getGpuResources.sh
spark.executor.resource.gpu.amount=1
spark.executor.resource.gpu.discoveryScript=./getGpuResources.sh
spark.task.resource.gpu.amount=0.25

6.
Stage Level Scheduling

7.
Overview
Spark ETL Stage Spark ML Stage
NODE NODE
GPU
CPU
CPU

8.
Stage Level Scheduling
• Stage level resource scheduling (SPARK-27495)
• Specify resource requirements per RDD operation
• Spark dynamically allocates containers to meet resource requirements
• Spark schedules tasks on appropriate containers
• Benefits
• Hardware utilization and cost
• Ease of programming
• Application no longer required split ETL and Deep Learning into separate
applications
• Pipeline simplification

9.
Use Cases
• Beneficial any time the user wants to change container resources between
stages in a single Spark application
• ETL to Deep Learning
• Skewed data
• Data size large in certain stages
• Jobs that use caching, switch to higher memory containers during those
stages

10.
Resources Supported
• Executor Resources
• Cores
• Heap Memory
• OffHeap Memory
• Pyspark Memory
• Memory Overhead
• Additional Resources (GPUs, etc)
• Task Resources
• CPUs
• Additional Resources (GPUs, etc)

11.
Requirements
• Spark 3.1.1
• Dynamic Allocation with External Shuffle Service or Shuffle tracking
enabled
• YARN and Kubernetes
• RDD API only
• Scala, Java, Python

12.
Implementation Details
• New container acquired with new ResourceProfile
• Does NOT try to fit into existing container with different ResourceProfile
(Future Enhancement)
• Unused containers idle timeout
• Default to one ResourceProfile per stage
• Config to allow multiple ResourceProfiles per stage
• Multiple profiles will be merged with simple max of each resource

13.
YARN Implementation Details
• External Shuffle Service and Dynamic Allocation
• YARN Container Priority – ResourceProfile Id becomes container priority
• YARN lower numbers are higher priority
• Job Server type scenario that may come into affect
• GPU and FPGA predefined, other resources require additional
configurations
• Custom resources via spark.yarn.executor.resource.* only apply in default
profile – do not propogate because no way to override
• Discovery script must be accessible – sent with job submission

14.
Kubernetes Implementation Details
• Requires shuffle tracking enabled
(spark.dynamicAllocaiton.shuffleTracking.enabled)
• May not idel timeout if have shuffle data on the node
• Result in more cluster resource used
• spark.dynamicAllocaiton.shuffleTracking.timeout
• Pod Template Behavior
• Resource in Pod Template only used in default profile
• Specify all resources needed in the ResourceProfile

15.
UI Screen Shots
--executor-cores 2 --conf spark.executor.resource.gpu.amount=1 --conf spark.task.resource.gpu.amount=0.5

16.
UI Screen Shots

17.
API
> import org.apache.spark.resource.{ExecutorResourceRequests, ResourceProfileBuilder,
TaskResourceRequests}
> val rpb = new ResourceProfileBuilder()
> val ereq = new ExecutorResourceRequests()
> val treq = new TaskResourceRequests()
> ereq.cores(4).memory("6g”).memoryOverhead("2g”).resource("gpu", 2, "./getGpus")
> treq.cpus(4).resource("gpu", 2)
> rpb.require(ereq)
> rpb.require(treq)
> val rp = rpb.build()
// use the ResourceProfile with the RDD
> val mlRdd = df.rdd.withResources(rp)
> mlRdd.mapPartitions { x =>
// feed data into ML and get result
}.collect()

18.
UI Screen Shots

19.
UI Screen Shots

20.
API
> rpb
Profile executor resources: ArrayBuffer(memoryOverhead=name: memoryOverhead, amount:
2048, script: , vendor: , cores=name: cores, amount: 4, script: , vendor: , memory=name:
memory, amount: 6144, script: , vendor: , gpu=name: gpu, amount: 2, script: ./getGpus,
vendor: ), task resources: ArrayBuffer(cpus=name: cpus, amount: 4.0, gpu=name: gpu,
amount: 2.0)
> mlRdd.getResourceProfile
: org.apache.spark.resource.ResourceProfile = Profile: id = 1, executor resources:
memoryOverhead -> name: memoryOverhead, amount: 2048, script: , vendor: ,cores -> name:
cores, amount: 4, script: , vendor: ,memory -> name: memory, amount: 6144, script: ,
vendor: ,gpu -> name: gpu, amount: 2, script: ./getGpus, vendor: , task resources: cpus
-> name: cpus, amount: 4.0,gpu -> name: gpu, amount: 2.0

21.
API - Mutable vs Immutable
> ereq.cores(2).memory("6g”).memoryOverhead("2g”).resource("gpu", 2, "./getGpus")
> treq.cpus(1).resource("gpu", 1)
> rpb.require(ereq).require(treq)
> val rp = rpb.build()
> rp
: org.apache.spark.resource.ResourceProfile = Profile: id = 2, executor resources: memoryOverhead ->
name: memoryOverhead, amount: 2048, script: , vendor: ,cores -> name: cores, amount: 2, script: , vendor:
,memory -> name: memory, amount: 6144, script: , vendor: ,gpu -> name: gpu, amount: 2, script: ./getGpus,
vendor: , task resources: cpus -> name: cpus, amount: 1.0,gpu -> name: gpu, amount: 1.0
> treq.cpus(2).resource("gpu", 2)
> rpb.require(treq)
> val rpNew = rpb.build()
> rpNew
: org.apache.spark.resource.ResourceProfile = Profile: id = 3, executor resources: memoryOverhead ->
name: memoryOverhead, amount: 2048, script: , vendor: ,cores -> name: cores, amount: 2, script: , vendor:
,memory -> name: memory, amount: 6144, script: , vendor: ,gpu -> name: gpu, amount: 2, script: ./getGpus,
vendor: , task resources: cpus -> name: cpus, amount: 2.0,gpu -> name: gpu, amount: 2.0

22.
Use Case Example
End to End Pipeline

23.
ETL Using Rapids Accelerator For Spark

24.
Rapids Accelerator For Spark
• Run Spark on a GPU to accelerate processing
• combines the power of the RAPIDS cuDF library and the scale of the Spark distributed
computing framework
• Spark SQL and DataFrames
• Requires Spark 3.0+
• No user code changes
• If operation not supported, run on CPU like normal
• built-in accelerated shuffle based on UCX that can be configured to
leverage GPU-to-GPU communication and RDMA capabilities’

25.
ETL Technology Stack
Dask cuDF
cuDF, Pandas
Python
Cython
cuDF C++
CUDA Libraries
CUDA
Java
JNI bindings
Spark dataframes,
Scala, PySpark

26.
Rapids Accelerator For Apache Spark (Plugin)
DISTRIBUTED SCALE-OUT SPARK APPLICATIONS
APACHE SPARK CORE
RAPIDS
Accelerator
for Spark
Spark SQL API DataFrame API Spark Shuffle
if gpu_enabled(operation, data_type)
call-out to RAPIDS
else
execute standard Spark operation
● Custom Implementation of Spark
Shuffle
● Optimized to use RDMA and GPU-
to-GPU direct communication
JNI bindings
Mapping From Java/Scala to C++
RAPIDS C++ Libraries UCX Libraries
CUDA
JNI bindings
Mapping From Java/Scala to C++

27.
Spark SQL & Dataframe Compilation Flow
DataFrame
Logical Plan
Physical Plan
bar.groupBy(
col(”product_id”),
col(“ds”))
.agg(
maxcol(“price”)) -
min(col(“p(rice”)).alias(“range”))
SELECT product_id, ds,
max(price) – min(price) AS
range FROM bar GROUP BY
product_id, ds
QUERY
GPU
PHYSICAL
PLAN
GPU Physical Plan
RAPIDS SQL
Plugin
RDD[InternalRow]
RDD[ColumnarBatch]

28.
NDS Query 38 Results
Entire query is GPU accelerated
CPU Cluster: Driver: 1 x m5dn.large;
Workers: 8 x m5dn.2xlarge
On-demand cluster cost (US West): $4.488/hr
GPU Cluster: Driver: 1 x m5dn.large;
Workers: 8 x g4dn.2xlarge
On-demand cluster cost (US West): $6.152/hr
163.0
53.2
0.0
40.0
80.0
120.0
160.0
200.0
CPU: 8 x m5dn.2xlarge
(64-core 256GB)
GPU: 8 x g4dn.2xlarge
(64-core 256GB 8xT4
GPU)
Time
(secs)
Query Time
$0.20
$0.09
$0.00
$0.05
$0.10
$0.15
$0.20
$0.25
CPU: 8 x m5dn.2xlarge
(64-core 256GB)
GPU: 8 x g4dn.2xlarge
(64-core 256GB 8xT4 GPU)
Total Costs
3X Speed-up 55% Cost Saving

29.
Deep Learning

30.
Horovod Introduction
• Distributed Deep learning training framework
• TensorFlow, Keras, PyTorch, Apache MXNet
• High Performance features
• NCCL< GpuDirect, RDMA, tensor fusion
• Easy to use
• Just 5 lines of Python
• Open Source
• Linux Foundation AI Foundation
• Easy to install
• pip install horovod
horovod.ai

31.
Demo

32.
End to End Horovod Demo

33.
Future Enhancements

34.
Future Enhancements
• Collect feedback from users
• Allow setting certain configs – like dynamic allocation
• Fitting new ResourceProfiles into existing containers
• Better cleanup of ResourceProfiles
• Catalyst internally

35.
Other Performance Enhancements

36.
Other Enhancements
• Pluggable Caching
• Allows developers to try different caching solutions
• Custom GPU implementation

37.
Questions

38.
Feedback
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