kandi X-RAY | jmh Summary
kandi X-RAY | jmh Summary
JMH is a Java harness for building, running, and analysing nano/micro/milli/macro benchmarks written in Java and other languages targeting the JVM.
Support
Quality
Security
License
Reuse
Top functions reviewed by kandi - BETA
- Runs benchmark
- Set the blackhole options
- Prints the JMH version
- List supported profiles
- Main entry point
- Set the blackhole options
- Prints the JMH version
- List supported profiles
- Writes out a collection of results
- Takes a string and converts it to a string
- Writes a collection of results to the output file
- Convert class names to denser class names
- Runs the sample algorithm
- Decode a String
- Initializes the variables
- Called after a test is executed
- Writes the given results to the output
- Visit this class
- Starts parsing events
- Discover all classes that have been annotated
- Starts the application
- Distribute threads to a list of threads
- Invokes the method on the proxy
- Called after an iteration
- Parses the init line
- Command - line tool
- Encode base64
- Read events from the file
- Starts the benchmark
jmh Key Features
jmh Examples and Code Snippets
Community Discussions
Trending Discussions on jmh
QUESTION
I'm running the following benchmark on Java 17:
...ANSWER
Answered 2022-Apr-04 at 21:54I assume that the costs of calling String.valueOf() within benchmark method remained the same
It is not. In the first case, the method argument is constant, so JIT can apply the Constant Propagation optimization.
Consider a very simplified example:
QUESTION
I've an ArrayList of 50M, I would like to measure time it takes to store that many objects in it. It seems as all JMH modes are time based, we can't really control number of executions of code under @Benchmark. For examlpe, how can I ensure the following code is run exactly 50M times per fork?
...ANSWER
Answered 2022-Mar-21 at 15:47You can create a benchmark class (ArrayListBenchmark) and a runner class (BenchmarkRunner).
- In
ArrayListBenchmarkclass, you can add the benchmark method that iterates the desired number of times adding items to theList. - In
BenchmarkRunnerclass, you set the desired number of items to add to theListand config the runner options.
Note: Depending on your environment, adding 50M items may throw an OutOfMemoryError.
Benchmark class:
QUESTION
I run sample JHM benchmark which suppose to show dead code elimination. Code is rewritten for conciseness from jhm github sample.
...ANSWER
Answered 2022-Feb-09 at 17:17Those samples depend on JDK internals.
Looks like since JDK 9 and JDK-8152907, Math.log is no longer intrinsified into C2 intermediate representation. Instead, a direct call to a quick LIBM-backed stub is made. This is usually faster for the code that actually uses the result. Notice how measureCorrect is faster in JDK 17 output in your case.
But for JMH samples, it limits the the compiler optimizations around the Math.log, and dead code / folding samples do not work properly. The fix it to make samples that do not rely on JDK internals without a good reason, and instead use a custom written payload.
This is being done in JMH here:
QUESTION
I have a function like this:
...ANSWER
Answered 2022-Jan-31 at 20:57Equivalent immutable one-liner is:
QUESTION
Looking into UTF8 decoding performance, I noticed the performance of protobuf's UnsafeProcessor::decodeUtf8 is better than String(byte[] bytes, int offset, int length, Charset charset) for the following non ascii string: "Quizdeltagerne spiste jordbær med flØde, mens cirkusklovnen".
I tried to figure out why, so I copied the relevant code in String and replaced the array accesses with unsafe array accesses, same as UnsafeProcessor::decodeUtf8.
Here are the JMH benchmark results:
ANSWER
Answered 2022-Jan-12 at 09:52To measure the branch you are interested in and particularly the scenario when while loop becomes hot, I've used the following benchmark:
QUESTION
The JLS states, that for arrays, "The enhanced for statement is equivalent to a basic for statement of the form". However if I check the generated bytecode for JDK8, for both variants different bytecode is generated, and if I try to measure the performance, surprisingly, the enhanced one seems to be giving better results(on jdk8)... Can someone advise why it's that? I'd guess it's because of incorrect jmh testing, so if it's that, please suggest how to fix that. (I know that JMH states not to test using loops, but I don't think this applies here, as I'm actually trying to measure the loops here)
My JMH testing was rather simple (probably too simple), but I cannot explain the results. Testing JMH code is below, typical results are:
...ANSWER
Answered 2022-Jan-05 at 19:41TL;DR: You are observing what happens when JIT compiler cannot trust that values are not changing inside the loop. Additionally, in the tiny benchmark like this, Blackhole.consume costs dominate, obscuring the results.
Simplifying the test:
QUESTION
Following this post :
jfr is supported natively in openjdk 11
and it is confirmed by the features list of OpenJDK 11:
328: Flight Recorder
However, from this DZone article, about using JFR-linked option -XX:+UnlockCommercialFeatures:
OpenJDK doesn’t recognize this option
And when I try for ex. with Gradle: ./gradlew clean -Dorg.gradle.jvmargs="-XX:+UnlockCommercialFeatures" I get
Process command line: C:\Program Files\AdoptOpenJDK\jdk-11.0.11.9-hotspot\bin\java.exe -XX:+UnlockCommercialFeatures (...)
Unrecognized VM option 'UnlockCommercialFeatures'
What am I missing here ?
...ANSWER
Answered 2021-Nov-16 at 07:09JFR was a commercial feature in Oracle Java up to Java 1.8 that needed to be specially enabled (using -XX:+UnlockCommercialFeatures).
With Java 11 and later it is no longer a commercial feature so you don't need this flag.
Actually the linked article states:
JFR Packaging Differences
Oracle JDK 11 emits a warning when using the-XX:+UnlockCommercialFeaturesoption, whereas OpenJDK doesn’t recognize this option and reports an error.
And the example below that the author shows doesn't use the -XX:+UnlockCommercialFeatures.
QUESTION
Please, read the newest EDIT of this question.
Issue: I need to write a correct benchmark to compare a different work using different Thread Pool realizations (also from external libraries) using different methods of execution to other work using other Thread Pool realizations and to a work without any threading.
For example I have 24 tasks to complete and 10000 random Strings in benchmark state:
...ANSWER
Answered 2021-Oct-29 at 14:03See answers to this question to learn how to write benchmarks in java.
... executorService maybe correct (but i am still unsure) ...
QUESTION
I've been attempting to run benchmarks to compare how many ops/ms for the add method of ArrayLists and LinkedLists in Java. My benchmarks are set up as follows but I can't pinpoint what is causing the out of memory error. Possibly the initialisation of the lists in the setup method?
...ANSWER
Answered 2021-Nov-09 at 19:58Disclaimer: it's not a answer to the question. But I wanted to share with OP my findings, which would not fit so well in a comment.
I encountered on my system a different exception:
QUESTION
I'm running a benchmark from IDEA on MacOS with DTraceAsmProfiler and it fails with this error:
ANSWER
Answered 2021-Oct-29 at 08:57Finally I've found the solution:
Community Discussions, Code Snippets contain sources that include Stack Exchange Network
Vulnerabilities
No vulnerabilities reported
Install jmh
Gradle JMH Plugin
Scala SBT JMH Plugin
Support
Reuse Trending Solutions
Find, review, and download reusable Libraries, Code Snippets, Cloud APIs from over 650 million Knowledge Items
Find more librariesStay Updated
Subscribe to our newsletter for trending solutions and developer bootcamps
Share this Page
