Added section about async profiler with cf java #1771
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Spelling Mistakes
- java/operating-applications/optimizing.md:56:8 Unknown word "Asprof"
- java/operating-applications/optimizing.md:57:34 Unknown word "asprof"
Generally, for each spelling mistake there are 2 ways to fix it:
- Fix the spelling mistake and commit it.
- The word is incorrectly reported as misspelled → put the word on the project-words.txt list, located in the root project directory.
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| #### Examples | ||
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| 1. Profile `sample-app-srv` for 30 seconds, write output into a file `profile.jfr` and download the file from the container to the local directory `~/tmp`: |
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what kind of profiling is startet? cpu or alloc or both? I think we should show most important flavours: cpu pofiling and alloc trace. We should at least name the available traces in async profiler (contention, gc, ...)
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Per default it's cpu profiling. But I've just talked with Johannes a little bit.
In my opinion currently there are too many asprof command variants in cf java and their use cases are not clearly distinguishable: https://github.com/SAP/cf-cli-java-plugin?tab=readme-ov-file#commands.
There's
- asprof
- start-asprof
- stop-asprof
- asprof-status
- start-asprof-cpu-profile
- start-asprof-wall-clock-profile
These are too many variants, and are not very much more useful to begin with, as you can do everything with just cf java asprof.
For example for wall-clock profiling. Instead of
cf java start-asprof-wall-clock-profile app-srv
you could just use
cf java asprof app-srv -a 'start -e wall'
which users that have been working with asprof already would be more familiar with.
Johannes agreed with me and will talk with Andreas Steiner, and they might reduce the command options to just asprof. Then documenting this in Capire will also be easier.
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und wie wäre es mit
cf java asprof app-srv start -cpu
cf java asprof app-srv start -wall
cf java asprof app-srv start -alloc
cf java asprof app-srv start -lock
cf java asprof app-srv start -a 'start -e wall' // expert mode
cf java asprof app-srv stop -file:<> // file optional
cf java asprof app-srv status
ich finde das intuitiver als die -a Option. Die kann gerne noch als Breakout angeboten sein, aber der 99%-User wird sicher zu den Shortcuts greifen
| Choosing an output filename with .html ending indicates to use the output type `flamegraph`, see [FlameGraph visualization](https://github.com/async-profiler/async-profiler/blob/master/docs/GettingStarted.md#flamegraph-visualization) | ||
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| `.html` files can be opened in a browser, `.jfr` files can be viewed with a viewer such as [OpenJDK Mission Control](https://openjdk.org/projects/jmc/). |
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can jfr files also be opened in intellij or vscode?
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In IntelliJ only with the Ultimate Edition. For VSCode I'm not aware of any extension that could open jfr files.
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Johannes hat ein PLugin für intellij gebaut - nur das ist eher noch instabil. Du kannst ihn ja fragen, ob wir es schon verlinken sollen
Added section about how to use the https://github.com/SAP/cf-cli-java-plugin to run profiling with asprof.