You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
arthas/en/_sources/profiler.md.txt

171 lines
3.7 KiB
Plaintext

profiler
===
> Generate a flame graph using [async-profiler](https://github.com/jvm-profiling-tools/async-profiler)
The `profiler` command supports generate flame graph for application hotspots.
The basic usage of the `profiler` command is `profiler action [actionArg]`
### Start profiler
```
$ profiler start
Started [cpu] profiling
```
> By default, the sample event is `cpu`. Can be specified with the `--event` parameter.
### Get the number of samples collected
```
$ profiler getSamples
23
```
### View profiler status
```bash
$ profiler status
[cpu] profiling is running for 4 seconds
```
Can view which `event` and sampling time.
### Stop profiler
#### Generate svg format results
```
$ profiler stop
profiler output file: /tmp/demo/arthas-output/20191125-135546.svg
OK
```
By default, the generated results are saved to the `arthas-output` directory under the application's `working directory`. The output result path can be specified by the `--file` parameter. such as:
```bash
$ profiler stop --file /tmp/output.svg
profiler output file: /tmp/output.svg
OK
```
#### Generating html format results
By default, the result file is `svg` format. If you want to generate the `html` format, you can specify it with the `--format` parameter:
```bash
$ profiler stop --format html
profiler output file: /tmp/test/arthas-output/20191125-143329.html
OK
```
Or use the file name name format in the `--file` parameter. For example, `--file /tmp/result.html`.
### View profiler results under arthas-output via browser
By default, arthas uses port 3658, which can be opened: [http://localhost:3658/arthas-output/](http://localhost:3658/arthas-output/) View the `arthas-output` directory below Profiler results:
![](_static/arthas-output.jpg)
Click to view specific results:
![](_static/arthas-output-svg.jpg)
> If using the chrome browser, may need to be refreshed multiple times.
### Profiler supported events
Under different platforms and different OSs, the supported events are different. For example, under macos:
```bash
$ profiler list
Basic events:
cpu
alloc
lock
wall
itimer
```
Under linux
```bash
$ profiler list
Basic events:
cpu
alloc
lock
wall
itimer
Perf events:
page-faults
context-switches
cycles
instructions
cache-references
cache-misses
branches
branch-misses
bus-cycles
L1-dcache-load-misses
LLC-load-misses
dTLB-load-misses
mem:breakpoint
trace:tracepoint
```
If you encounter the permissions/configuration issues of the OS itself and then missing some events, you can refer to the [async-profiler](https://github.com/jvm-profiling-tools/async-profiler) documentation.
You can use the `--event` parameter to specify the event to sample, such as sampling the `alloc` event:
```bash
$ profiler start --event alloc
```
### Resume sampling
```bash
$ profiler resume
Started [cpu] profiling
```
The difference between `start` and `resume` is: `start` is the new start sampling, `resume` will retain the data of the last `stop`.
You can verify the number of samples by executing `profiler getSamples`.
### Use `execute` action to execute complex commands
For example, start sampling:
```bash
profiler execute 'start'
```
Stop sampling and save to the specified file:
```bash
profiler execute 'stop,file=/tmp/result.svg'
```
Specific format reference: [arguments.cpp#L34](https://github.com/jvm-profiling-tools/async-profiler/blob/v1.6/src/arguments.cpp#L34)
### View all supported actions
```bash
$ profiler actions
Supported Actions: [resume, dumpCollapsed, getSamples, start, list, execute, version, stop, load, dumpFlat, actions, dumpTraces, status]
```
### View version
```bash
$ profiler version
Async-profiler 1.6 built on Sep 9 2019
Copyright 2019 Andrei Pangin
```