Tag Archives: profiling

A new Spark plugin for CPU and memory profiling

Post Syndicated from Bo Xiong original https://aws.amazon.com/blogs/devops/a-new-spark-plugin-for-cpu-and-memory-profiling/


Have you ever wondered if there are low-hanging optimization opportunities to improve the performance of a Spark app? Profiling can help you gain visibility regarding the runtime characteristics of the Spark app to identify its bottlenecks and inefficiencies. We’re excited to announce the release of a new Spark plugin that enables profiling for JVM based Spark apps via Amazon CodeGuru. The plugin is open sourced on GitHub and published to Maven.


This post shows how you can onboard this plugin with two steps in under 10 minutes.

  • Step 1: Create a profiling group in Amazon CodeGuru Profiler and grant permission to your Amazon EMR on EC2 role, so that profiler agents can emit metrics to CodeGuru. Detailed instructions can be found here.
  • Step 2: Reference codeguru-profiler-for-spark when submitting your Spark job, along with PROFILING_CONTEXT and ENABLE_AMAZON_PROFILER defined.


Your app is built against Spark 3 and run on Amazon EMR release 6.x or newer. It doesn’t matter if you’re using Amazon EMR on Amazon Elastic Compute Cloud (Amazon EC2) or on Amazon Elastic Kubernetes Service (Amazon EKS).

Illustrative Example

For the purposes of illustration, consider the following example where profiling results are collected by the plugin and emitted to the “CodeGuru-Spark-Demo” profiling group.

spark-submit \
--master yarn \
--deploy-mode cluster \
--class \
--packages software.amazon.profiler:codeguru-profiler-for-spark:1.0 \
--conf spark.plugins=software.amazon.profiler.AmazonProfilerPlugin \
--conf spark.executorEnv.PROFILING_CONTEXT="{\\\"profilingGroupName\\\":\\\"CodeGuru-Spark-Demo\\\"}" \
--conf spark.executorEnv.ENABLE_AMAZON_PROFILER=true \
--conf spark.dynamicAllocation.enabled=false \t

An alternative way to specify PROFILING_CONTEXT and ENABLE_AMAZON_PROFILER is under the yarn-env.export classification for instance groups in the Amazon EMR web console. Note that PROFILING_CONTEXT, if configured in the web console, must escape all of the commas on top of what’s for the above spark-submit command.

    "classification": "yarn-env",
    "properties": {},
    "configurations": [
        "classification": "export",
        "properties": {
          "ENABLE_AMAZON_PROFILER": "true",
          "PROFILING_CONTEXT": "{\\\"profilingGroupName\\\":\\\"CodeGuru-Spark-Demo\\\"\\,\\\"driverEnabled\\\":\\\"true\\\"}"
        "configurations": []

Once the job above is launched on Amazon EMR, profiling results should show up in your CodeGuru web console in about 10 minutes, similar to the following screenshot. Internally, it has helped us identify issues, such as thread contentions (revealed by the BLOCKED state in the latency flame graph), and unnecessarily create AWS Java clients (revealed by the CPU Hotspots view).

Go to your profiling group under the Amazon CodeGuru web console. Click the “Visualize CPU” button to render a flame graph displaying CPU usage. Switch to the latency view to identify latency bottlenecks, and switch to the heap summary view to identify objects consuming most memory.


To help with troubleshooting, use a sample Spark app provided in the plugin to check if everything is set up correctly. Note that the profilingGroupName value specified in PROFILING_CONTEXT should match what’s created in CodeGuru.

spark-submit \
--master yarn \
--deploy-mode cluster \
--class software.amazon.profiler.SampleSparkApp \
--packages software.amazon.profiler:codeguru-profiler-for-spark:1.0 \
--conf spark.plugins=software.amazon.profiler.AmazonProfilerPlugin \
--conf spark.executorEnv.PROFILING_CONTEXT="{\\\"profilingGroupName\\\":\\\"CodeGuru-Spark-Demo\\\"}" \
--conf spark.executorEnv.ENABLE_AMAZON_PROFILER=true \
--conf spark.yarn.appMasterEnv.PROFILING_CONTEXT="{\\\"profilingGroupName\\\":\\\"CodeGuru-Spark-Demo\\\",\\\"driverEnabled\\\":\\\"true\\\"}" \
--conf spark.yarn.appMasterEnv.ENABLE_AMAZON_PROFILER=true \
--conf spark.dynamicAllocation.enabled=false \

Running the command above from the master node of your EMR cluster should produce logs similar to the following:

21/11/21 21:27:21 INFO Profiler: Starting the profiler : ProfilerParameters{profilingGroupName='CodeGuru-Spark-Demo', threadSupport=BasicThreadSupport (default), excludedThreads=[Signal Dispatcher, Attach Listener], shouldProfile=true, integrationMode='', memoryUsageLimit=104857600, heapSummaryEnabled=true, stackDepthLimit=1000, samplingInterval=PT1S, reportingInterval=PT5M, addProfilerOverheadAsSamples=true, minimumTimeForReporting=PT1M, dontReportIfSampledLessThanTimes=1}
21/11/21 21:27:21 INFO ProfilingCommandExecutor: Profiling scheduled, sampling rate is PT1S
21/11/21 21:27:23 INFO ProfilingCommand: New agent configuration received : AgentConfiguration(AgentParameters={MaxStackDepth=1000, MinimumTimeForReportingInMilliseconds=60000, SamplingIntervalInMilliseconds=1000, MemoryUsageLimitPercent=10, ReportingIntervalInMilliseconds=300000}, PeriodInSeconds=300, ShouldProfile=true)
21/11/21 21:32:23 INFO ProfilingCommand: Attempting to report profile data: start=2021-11-21T21:27:23.227Z end=2021-11-21T21:32:22.765Z force=false memoryRefresh=false numberOfTimesSampled=300
21/11/21 21:32:23 INFO javaClass: [HeapSummary] Processed 20 events.
21/11/21 21:32:24 INFO ProfilingCommand: Successfully reported profile

Note that the CodeGuru Profiler agent uses a reporting interval of five minutes. Therefore, any executor process shorter than five minutes won’t be reflected by the profiling result. If the right profiling group is not specified, or it’s associated with a wrong EC2 role in CodeGuru, then the log will show a message similar to “CodeGuruProfilerSDKClient: Exception while calling agent orchestration” along with a stack trace including a 403 status code. To rule out any network issues (e.g., your EMR job running in a VPC without an outbound gateway or a misconfigured outbound security group), then you can remote into an EMR host and ping the CodeGuru endpoint in your Region (e.g., ping codeguru-profiler.us-east-1.amazonaws.com).

Cleaning up

To avoid incurring future charges, you can delete the profiling group configured in CodeGuru and/or set the ENABLE_AMAZON_PROFILER environment variable to false.


In this post, we describe how to onboard this plugin with two steps. Consider to give it a try for your Spark app? You can find the Maven artifacts here. If you have feature requests, bug reports, feedback of any kind, or would like to contribute, please head over to the GitHub repository.


Bo Xiong

Bo Xiong is a software engineer with Amazon Ads, leveraging big data technologies to process petabytes of data for billing and reporting. His main interests include performance tuning and optimization for Spark on Amazon EMR, and data mining for actionable business insights.

Understanding memory usage in your Java application with Amazon CodeGuru Profiler

Post Syndicated from Fernando Ciciliati original https://aws.amazon.com/blogs/devops/understanding-memory-usage-in-your-java-application-with-amazon-codeguru-profiler/

“Where has all that free memory gone?” This is the question we ask ourselves every time our application emits that dreaded OutOfMemoyError just before it crashes. Amazon CodeGuru Profiler can help you find the answer.

Thanks to its brand-new memory profiling capabilities, troubleshooting and resolving memory issues in Java applications (or almost anything that runs on the JVM) is much easier. AWS launched the CodeGuru Profiler Heap Summary feature at re:Invent 2020. This is the first step in helping us, developers, understand what our software is doing with all that memory it uses.

The Heap Summary view shows a list of Java classes and data types present in the Java Virtual Machine heap, alongside the amount of memory they’re retaining and the number of instances they represent. The following screenshot shows an example of this view.

Amazon CodeGuru Profiler heap summary view example

Figure: Amazon CodeGuru Profiler Heap Summary feature

Because CodeGuru Profiler is a low-overhead, production profiling service designed to be always on, it can capture and represent how memory utilization varies over time, providing helpful visual hints about the object types and the data types that exhibit a growing trend in memory consumption.

In the preceding screenshot, we can see that several lines on the graph are trending upwards:

  • The red top line, horizontal and flat, shows how much memory has been reserved as heap space in the JVM. In this case, we see a heap size of 512 MB, which can usually be configured in the JVM with command line parameters like -Xmx.
  • The second line from the top, blue, represents the total memory in use in the heap, independent of their type.
  • The third, fourth, and fifth lines show how much memory space each specific type has been using historically in the heap. We can easily spot that java.util.LinkedHashMap$Entry and java.lang.UUID display growing trends, whereas byte[] has a flat line and seems stable in memory usage.

Types that exhibit constantly growing trend of memory utilization with time deserve a closer look. Profiler helps you focus your attention on these cases. Associating the information presented by the Profiler with your own knowledge of your application and code base, you can evaluate whether the amount of memory being used for a specific data type can be considered normal, or if it might be a memory leak – the unintentional holding of memory by an application due to the failure in freeing-up unused objects. In our example above, java.util.LinkedHashMap$Entry and java.lang.UUIDare good candidates for investigation.

To make this functionality available to customers, CodeGuru Profiler uses the power of Java Flight Recorder (JFR), which is now openly available with Java 8 (since OpenJDK release 262) and above. The Amazon CodeGuru Profiler agent for Java, which already does an awesome job capturing data about CPU utilization, has been extended to periodically collect memory retention metrics from JFR and submit them for processing and visualization via Amazon CodeGuru Profiler. Thanks to its high stability and low overhead, the Profiler agent can be safely deployed to services in production, because it is exactly there, under real workloads, that really interesting memory issues are most likely to show up.


For more information about CodeGuru Profiler and other AI-powered services in the Amazon CodeGuru family, see Amazon CodeGuru. If you haven’t tried the CodeGuru Profiler yet, start your 90-day free trial right now and understand why continuous profiling is becoming a must-have in every production environment. For Amazon CodeGuru customers who are already enjoying the benefits of always-on profiling, this new feature is available at no extra cost. Just update your Profiler agent to version 1.1.0 or newer, and enable Heap Summary in your agent configuration.


Happy profiling!