jmh-samples | JMH examples with my own examples jar etc | Computer Vision library
kandi X-RAY | jmh-samples Summary
kandi X-RAY | jmh-samples Summary
JMH samples. This was setup to support my 2 blog posts about JMH: And contains the examples discussed under the psy.lob.saw package. The JMH framework is hosted here: The JMH samples are a MUST read (and are always up to date):
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Top functions reviewed by kandi - BETA
- Benchmarks a custom Encoder using buffered encoder
- Encodes the given source and destination address
- Encodes a UTF - 8 string into the ByteBuffer
- Encodes a String into a ByteBuffer
- Sets up the benchmark
- Close reader
- Closes the given stream
- Wrap a string with a buffered character buffer
- Wrap a char buffer
- Get char array from String
- Prints WOW
- Builds a String from a char array
- Benchmarks a string using UTF - 8
- Allocates a new big - end byte buffer with the specified size
- This method is used for testing purposes
- Measure the shared counter for this thread
- Measure an unshared counter
- Measure shared counter
- Measure counter for unshared counter
- Indicates if an address is aligned
- Converts a string into a char buffer
- Loops through the beat loop
- The number of charset encoder
- Benchmarks a cold loop
jmh-samples Key Features
jmh-samples Examples and Code Snippets
Community Discussions
Trending Discussions on jmh-samples
QUESTION
I want to write a benchmark to keep track of maximum, minimum and average time required for the execution of some Java code.
I read about JMH (Java Microbenchmark Harness) and it seems to match my needs, but I'm not quite sure about which mode should I use:
Mode.Throughput
measures the raw throughput by continuously calling the benchmark method in a time-bound iteration, and counting how many times we executed the method.It seems not to be what I am looking for.
Mode.AverageTime
measures the average time it takes for your benchmark method to be executed.This should be 1/3 of my needs.
Mode.SingleShotTime
measures how long a single benchmark method execution takes to run.It seems not to be what I am looking for.
Mode.SampleTime
is the most obscure to me.Documentations on examples states that it "samples" the execution time, by running the method in a time-bound iteration, but instead of measuring the total time, it measures the time spent in "some" of the benchmark method calls. What does it mean?
What mode can provide me min and max times? Are there any more modes, or are there other frameworks to do the job?
...ANSWER
Answered 2021-Apr-04 at 18:35If you run your @Benchmark
with @BenchmarkMode(Mode.AverageTime)
, as a bonus, you will get an output like:
QUESTION
Considering the default usage of the JMH, I would like to make sure which type of time JMH bases its measurements on: CPU time or Wall-clock.
I tried looking into the JMH official samples (https://openjdk.java.net/projects/code-tools/jmh/), tutorials (at Jenkov, Baeldung, Mykong and others), and did not manage to find this information precisely (I acknowledge I might have missed some documentation or general information on benchmarks).
For instance, in Sample 35 (https://hg.openjdk.java.net/code-tools/jmh/file/99d7b73cf1e3/jmh-samples/src/main/java/org/openjdk/jmh/samples/JMHSample_35_Profilers.java), we have as an example of output:
...ANSWER
Answered 2019-Sep-27 at 23:01As I feared, I had missed basic information and formulated my question badly since wall-clock and CPU times are not the only options. I followed Alexandre Cartapanis' suggestion and looked into JMH's source code. I found out that the class BenchmarkGenerator, which produces the benchmarks, relies on System.nanoTime().
Further, according to System.nanoTime() documentation and Kevin Bourrillion's answer to another question I concluded that JMH, by default, measures time according to some arbitrary, but fixed, source (just like System.nanoTime()).
QUESTION
Wanted to start doing benchmark of methods that i will write from now onward, Had motivation from a long time and finally decided to do so from yesterday. But i have been struck with my setup process.
- I have installed the JMH plugin correctly.
- All imports works fine.
- Even my POM shows no error.
But when i run the command mvn clean install
, i get below error:
[ERROR] Failed to execute goal on project TestOptional: Could not resolve dependencies for project Vishwaratna:TestOptional:jar:1.0-SNAPSHOT: The following artifacts could not be resolve d: org.openjdk.jmh:jmh-core:jar:1.21, org.openjdk.jmh:jmh-generator-annprocess:jar:1.21: Could not find artifact org.openjdk.jmh:jmh-core:jar:1.21 in art_all (http://maven/artifactory/li bs-snapshot)
I thought that i must force update the repos, so i ran mvn -U clean install
, again no luck.
Did plenty of searches and went through N-number of SO threads, but still not able to figure out where i am going wrong.
When i just run my Testing.java class ,I get below message:
No matching benchmarks. Miss-spelled regexp?
Use EXTRA verbose mode to debug the pattern matching.
Process finished with exit code 1
I am confused that when maven is not able to find those JMH libs from central reps then why my code with all annotations are not showing red compilation error?? If the libs are imported correctly then why i am getting error that xx could not be downloaded when i run mvn clean install
from terminal?
After 2 hours of struggling, i thought to give up on POM.xml and tried to add jars manually, i downloaded , JMH annotation jar and JMH core jar and configured the paths manually. And guess what still no luck.
In case you wanna know what i am coding :
...ANSWER
Answered 2019-Apr-18 at 06:36I have successfully run your example.
The only thing I had to change was to put your Testing.java
into any package for example package t;
If you have any problems with your repo, please try if you do not have any strange settings in your settings.xml
file. https://maven.apache.org/settings.html. There may be some proxing set or something like that, which may change your expected behaviour of your project.
Change URLs in settings.xml
to https://repo1.maven.org/maven2/
Community Discussions, Code Snippets contain sources that include Stack Exchange Network
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No vulnerabilities reported
Install jmh-samples
You can use jmh-samples like any standard Java library. Please include the the jar files in your classpath. You can also use any IDE and you can run and debug the jmh-samples component as you would do with any other Java program. Best practice is to use a build tool that supports dependency management such as Maven or Gradle. For Maven installation, please refer maven.apache.org. For Gradle installation, please refer gradle.org .
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