mirror of https://github.com/sbt/sbt.git
Move PROFILING out of CONTRIBUTING
This commit is contained in:
Dale Wijnand
parent
76a621b996
commit
2a4406717c
151
CONTRIBUTING.md
151
CONTRIBUTING.md
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@ -232,156 +232,7 @@ command. To run a single test, such as the test in
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Profiling sbt
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-------------
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There are several ways to profile sbt. The new hotness in profiling is FlameGraph.
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You first collect stack trace samples, and then it is processed into svg graph.
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See:
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- [Using FlameGraphs To Illuminate The JVM by Nitsan Wakart](https://www.youtube.com/watch?v=ugRrFdda_JQ)
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- [USENIX ATC '17: Visualizing Performance with Flame Graphs](https://www.youtube.com/watch?v=D53T1Ejig1Q)
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### jvm-profiling-tools/async-profiler
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The first one I recommend is async-profiler. This is available for macOS and Linux,
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and works fairly well.
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1. Download the installer from https://github.com/jvm-profiling-tools/async-profiler/releases/tag/v1.2
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2. Make symbolic link to `build/` and `profiler.sh` to `$HOME/bin`, assuming you have PATH to `$HOME/bin`:
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`ln -s ~/Applications/async-profiler/profiler.sh $HOME/bin/profiler.sh`
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`ln -s ~/Applications/async-profiler/build $HOME/bin/build`
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Next, close all Java appliations and anything that may affect the profiling, and run sbt in one terminal:
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```
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$ sbt exit
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```
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In another terminal, run:
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```
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$ jps
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92746 sbt-launch.jar
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92780 Jps
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```
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This tells you the process ID of sbt. In this case, it's 92746. While it's running, run
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```
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$ profiler.sh -d 60 <process id>
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Started [cpu] profiling
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--- Execution profile ---
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Total samples: 31602
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Non-Java: 3239 (10.25%)
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GC active: 46 (0.15%)
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Unknown (native): 14667 (46.41%)
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Not walkable (native): 3 (0.01%)
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Unknown (Java): 433 (1.37%)
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Not walkable (Java): 8 (0.03%)
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Thread exit: 1 (0.00%)
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Deopt: 9 (0.03%)
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Frame buffer usage: 55.658%
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Total: 1932000000 (6.11%) samples: 1932
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[ 0] java.lang.ClassLoader$NativeLibrary.load
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[ 1] java.lang.ClassLoader.loadLibrary0
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[ 2] java.lang.ClassLoader.loadLibrary
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[ 3] java.lang.Runtime.loadLibrary0
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[ 4] java.lang.System.loadLibrary
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....
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```
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This should show a bunch of stacktraces that are useful.
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To visualize this as a flamegraph, run:
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```
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$ profiler.sh -d 60 -f /tmp/flamegraph.svg <process id>
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```
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This should produce `/tmp/flamegraph.svg` at the end.
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See https://gist.github.com/eed3si9n/82d43acc95a002876d357bd8ad5f40d5
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### running sbt with standby
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One of the tricky things you come across while profiling is figuring out the process ID,
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while wnating to profile the beginning of the application.
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For this purpose, we've added `sbt.launcher.standby` JVM flag.
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In the next version of sbt, you should be able to run:
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```
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$ sbt -J-Dsbt.launcher.standby=20s exit
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```
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This will count down for 20s before doing anything else.
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### jvm-profiling-tools/perf-map-agent
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If you want to try the mixed flamegraph, you can try perf-map-agent.
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This uses `dtrace` on macOS and `perf` on Linux.
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You first have to compile https://github.com/jvm-profiling-tools/perf-map-agent.
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For macOS, here to how to export `JAVA_HOME` before running `cmake .`:
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```
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$ export JAVA_HOME=$(/usr/libexec/java_home)
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$ cmake .
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-- The C compiler identification is AppleClang 9.0.0.9000039
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-- The CXX compiler identification is AppleClang 9.0.0.9000039
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...
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$ make
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```
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In addition, you have to git clone https://github.com/brendangregg/FlameGraph
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In a fresh termimal, run sbt with `-XX:+PreserveFramePointer` flag:
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```
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$ sbt -J-Dsbt.launcher.standby=20s -J-XX:+PreserveFramePointer exit
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```
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In the terminal that you will run the perf-map:
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```
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$ cd quicktest/
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$ export JAVA_HOME=$(/usr/libexec/java_home)
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$ export FLAMEGRAPH_DIR=$HOME/work/FlameGraph
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$ jps
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94592 Jps
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94549 sbt-launch.jar
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$ $HOME/work/perf-map-agent/bin/dtrace-java-flames 94549
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dtrace: system integrity protection is on, some features will not be available
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dtrace: description 'profile-99 ' matched 2 probes
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Flame graph SVG written to DTRACE_FLAME_OUTPUT='/Users/xxx/work/quicktest/flamegraph-94549.svg'.
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```
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This would produce better flamegraph in theory, but the output looks too messy for `sbt exit` case.
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See https://gist.github.com/eed3si9n/b5856ff3d987655513380d1a551aa0df
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This might be because it assumes that the operations are already JITed.
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### ktoso/sbt-jmh
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https://github.com/ktoso/sbt-jmh
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Due to JIT warmup etc, benchmarking is difficult. JMH runs the same tests multiple times to
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remove these effects and comes closer to measuring the performance of your code.
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There's also an integration with jvm-profiling-tools/async-profiler, apparently.
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### VisualVM
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I'd also mention traditional JVM profiling tool. Since VisualVM is opensource,
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I'll mention this one: https://visualvm.github.io/
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1. First VisualVM.
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2. Start sbt from a terminal.
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3. You should see `xsbt.boot.Boot` under Local.
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4. Open it, and select either sampler or profiler, and hit CPU button at the point when you want to start.
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If you are familiar with YourKit, it also works similarly.
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See [PROFILING](./PROFILING.md)
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Other notes for maintainers
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---------------------------
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@ -0,0 +1,153 @@
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Profiling sbt
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-------------
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There are several ways to profile sbt. The new hotness in profiling is FlameGraph.
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You first collect stack trace samples, and then it is processed into svg graph.
|
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See:
|
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|
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- [Using FlameGraphs To Illuminate The JVM by Nitsan Wakart](https://www.youtube.com/watch?v=ugRrFdda_JQ)
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- [USENIX ATC '17: Visualizing Performance with Flame Graphs](https://www.youtube.com/watch?v=D53T1Ejig1Q)
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### jvm-profiling-tools/async-profiler
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||||
|
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The first one I recommend is async-profiler. This is available for macOS and Linux,
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and works fairly well.
|
||||
|
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1. Download the installer from https://github.com/jvm-profiling-tools/async-profiler/releases/tag/v1.2
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2. Make symbolic link to `build/` and `profiler.sh` to `$HOME/bin`, assuming you have PATH to `$HOME/bin`:
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`ln -s ~/Applications/async-profiler/profiler.sh $HOME/bin/profiler.sh`
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`ln -s ~/Applications/async-profiler/build $HOME/bin/build`
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Next, close all Java appliations and anything that may affect the profiling, and run sbt in one terminal:
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```
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$ sbt exit
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```
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In another terminal, run:
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```
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$ jps
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92746 sbt-launch.jar
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92780 Jps
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```
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This tells you the process ID of sbt. In this case, it's 92746. While it's running, run
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```
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$ profiler.sh -d 60 <process id>
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Started [cpu] profiling
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--- Execution profile ---
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Total samples: 31602
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Non-Java: 3239 (10.25%)
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GC active: 46 (0.15%)
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Unknown (native): 14667 (46.41%)
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Not walkable (native): 3 (0.01%)
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Unknown (Java): 433 (1.37%)
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Not walkable (Java): 8 (0.03%)
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Thread exit: 1 (0.00%)
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Deopt: 9 (0.03%)
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Frame buffer usage: 55.658%
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Total: 1932000000 (6.11%) samples: 1932
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[ 0] java.lang.ClassLoader$NativeLibrary.load
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[ 1] java.lang.ClassLoader.loadLibrary0
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[ 2] java.lang.ClassLoader.loadLibrary
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[ 3] java.lang.Runtime.loadLibrary0
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[ 4] java.lang.System.loadLibrary
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....
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```
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This should show a bunch of stacktraces that are useful.
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To visualize this as a flamegraph, run:
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```
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$ profiler.sh -d 60 -f /tmp/flamegraph.svg <process id>
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```
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This should produce `/tmp/flamegraph.svg` at the end.
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See https://gist.github.com/eed3si9n/82d43acc95a002876d357bd8ad5f40d5
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### running sbt with standby
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One of the tricky things you come across while profiling is figuring out the process ID,
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while wnating to profile the beginning of the application.
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For this purpose, we've added `sbt.launcher.standby` JVM flag.
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In the next version of sbt, you should be able to run:
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```
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$ sbt -J-Dsbt.launcher.standby=20s exit
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```
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This will count down for 20s before doing anything else.
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|
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### jvm-profiling-tools/perf-map-agent
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||||
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If you want to try the mixed flamegraph, you can try perf-map-agent.
|
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This uses `dtrace` on macOS and `perf` on Linux.
|
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|
||||
You first have to compile https://github.com/jvm-profiling-tools/perf-map-agent.
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For macOS, here to how to export `JAVA_HOME` before running `cmake .`:
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```
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$ export JAVA_HOME=$(/usr/libexec/java_home)
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$ cmake .
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-- The C compiler identification is AppleClang 9.0.0.9000039
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-- The CXX compiler identification is AppleClang 9.0.0.9000039
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...
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$ make
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```
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In addition, you have to git clone https://github.com/brendangregg/FlameGraph
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In a fresh termimal, run sbt with `-XX:+PreserveFramePointer` flag:
|
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```
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$ sbt -J-Dsbt.launcher.standby=20s -J-XX:+PreserveFramePointer exit
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```
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In the terminal that you will run the perf-map:
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```
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$ cd quicktest/
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$ export JAVA_HOME=$(/usr/libexec/java_home)
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$ export FLAMEGRAPH_DIR=$HOME/work/FlameGraph
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$ jps
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94592 Jps
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94549 sbt-launch.jar
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$ $HOME/work/perf-map-agent/bin/dtrace-java-flames 94549
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dtrace: system integrity protection is on, some features will not be available
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dtrace: description 'profile-99 ' matched 2 probes
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Flame graph SVG written to DTRACE_FLAME_OUTPUT='/Users/xxx/work/quicktest/flamegraph-94549.svg'.
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```
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This would produce better flamegraph in theory, but the output looks too messy for `sbt exit` case.
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See https://gist.github.com/eed3si9n/b5856ff3d987655513380d1a551aa0df
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This might be because it assumes that the operations are already JITed.
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|
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### ktoso/sbt-jmh
|
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||||
https://github.com/ktoso/sbt-jmh
|
||||
|
||||
Due to JIT warmup etc, benchmarking is difficult. JMH runs the same tests multiple times to
|
||||
remove these effects and comes closer to measuring the performance of your code.
|
||||
|
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There's also an integration with jvm-profiling-tools/async-profiler, apparently.
|
||||
|
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### VisualVM
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|
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I'd also mention traditional JVM profiling tool. Since VisualVM is opensource,
|
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I'll mention this one: https://visualvm.github.io/
|
||||
|
||||
1. First VisualVM.
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2. Start sbt from a terminal.
|
||||
3. You should see `xsbt.boot.Boot` under Local.
|
||||
4. Open it, and select either sampler or profiler, and hit CPU button at the point when you want to start.
|
||||
|
||||
If you are familiar with YourKit, it also works similarly.
|
||||
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