Java profiling # https://cloud.google.com/profiler/docs/profiling-java

Java profiling.txt

$ wget -q -O- https://storage.googleapis.com/cloud-profiler/java/latest/profiler_java_agent.tar.gz | tar xzv
NOTICES
profiler_java_agent.so
libdataflow_profiler.jar

$ cat Test.java 
public class Test {
  private static void foo() {
    while (true) {}
  }

  public static void main(String[] argv) {
    foo();
  }
}

$ javac Test.java

$ java -agentpath:./profiler_java_agent.so=-logtostderr,-cprof_profile_filename=$PWD/profile_,-cprof_interval_sec=5,-cprof_duration_sec=10 Test
I0402 20:39:35.742357 140989 entry.cc:207] Profiler agent loaded
I0402 20:39:35.742499 140989 entry.cc:103] Prepare JVMTI
I0402 20:39:35.788872 140989 entry.cc:67] On VM init
I0402 20:39:35.789932 141005 throttler_timed.cc:61] Will save profiles to the local filesystem
I0402 20:39:35.789958 141005 throttler_timed.cc:75] sampling duration: cpu=10s, wall=10s
I0402 20:39:35.789969 141005 throttler_timed.cc:77] sampling interval: 5s
I0402 20:39:35.789978 141005 throttler_timed.cc:78] sampling delay: 0s
I0402 20:39:45.893823 141005 proto.cc:231] Collected a profile: total count=400, weight=40000000000
I0402 20:39:45.894408 141005 uploader_file.h:24] Saving profile to /usr/local/google/home/aalexand/projects/cprof-java-agent-collect-profile-to-file-example/profile_wall_1522726785.pb.gz
I0402 20:39:55.996594 141005 proto.cc:231] Collected a profile: total count=1000, weight=10000000000
I0402 20:39:55.996989 141005 uploader_file.h:24] Saving profile to /usr/local/google/home/aalexand/projects/cprof-java-agent-collect-profile-to-file-example/profile_cpu_1522726795.pb.gz
I0402 20:40:06.099144 141005 proto.cc:231] Collected a profile: total count=400, weight=40000000000
I0402 20:40:06.099649 141005 uploader_file.h:24] Saving profile to /usr/local/google/home/aalexand/projects/cprof-java-agent-collect-profile-to-file-example/profile_wall_1522726806.pb.gz
^CI0402 20:40:07.836849 141075 entry.cc:96] On VM death
I0402 20:40:16.201818 141005 proto.cc:231] Collected a profile: total count=1000, weight=10000000000
I0402 20:40:16.202256 141005 uploader_file.h:24] Saving profile to /usr/local/google/home/aalexand/projects/cprof-java-agent-collect-profile-to-file-example/profile_cpu_1522726816.pb.gz
I0402 20:40:16.202409 141005 worker.cc:116] Exiting the profiling loop

$ pprof -top profile_cpu_1522726816.pb.gz
File: java
Build ID: b8b4c6983f53365a453bf2958f19802be87f51fb
Type: cpu
Duration: 10s, Total samples = 10s (  100%)
Showing nodes accounting for 9.98s, 99.80% of 10s total
Dropped 2 nodes (cum <= 0.05s)
      flat  flat%   sum%        cum   cum%
     9.98s 99.80% 99.80%      9.98s 99.80%  Test.foo()
         0     0% 99.80%      9.98s 99.80%  JavaCalls::call_helper
         0     0% 99.80%      9.98s 99.80%  JavaMain
         0     0% 99.80%      9.98s 99.80%  Test.main
         0     0% 99.80%      9.98s 99.80%  WeakPreserveExceptionMark::~WeakPreserveExceptionMark (inline)
         0     0% 99.80%      9.98s 99.80%  __clone
         0     0% 99.80%      9.98s 99.80%  jni_CallStaticVoidMethod
         0     0% 99.80%      9.98s 99.80%  jni_invoke_static
         0     0% 99.80%      9.98s 99.80%  methodHandle::~methodHandle (inline)
         0     0% 99.80%      9.98s 99.80%  start_thread
         
 ~  ➜ go get -u github.com/google/pprof
 ~  ➜ go get github.com/gopalmor/gcvis
 ~  ➜ go tool pprof -http=":" -nodecount=9999999 profile_cpu_1606183305.pb.gz