Java性能分析工具Async-Profiler教程

apt install openjdk-8-dbg

apt install openjdk-11-dbg

gdb $JAVA_HOME/lib/server/libjvm.so -ex 'info address UseG1GC'

asprof -e wall -t -i 5ms -f result.html 8983

Usage: ./profiler.sh [action] [options] <pid>
Actions:
  start             start profiling and return immediately
  resume            resume profiling without resetting collected data
  stop              stop profiling
  dump              dump collected data without stopping profiling session
  check             check if the specified profiling event is available
  status            print profiling status
  meminfo           print profiler memory stats
  list              list profiling events supported by the target JVM
  collect           collect profile for the specified period of time
                    and then stop (default action)
Options:
  -e event          profiling event: cpu|alloc|lock|cache-misses etc.
  -d duration       run profiling for <duration> seconds
  -f filename       dump output to <filename>
  -i interval       sampling interval in nanoseconds
  -j jstackdepth    maximum Java stack depth
  -t                profile different threads separately
  -s                simple class names instead of FQN
  -g                print method signatures
  -a                annotate Java methods
  -l                prepend library names
  -o fmt            output format: flat|traces|collapsed|flamegraph|tree|jfr
  -I include        output only stack traces containing the specified pattern
  -X exclude        exclude stack traces with the specified pattern
  -v, --version     display version string

  --title string    FlameGraph title
  --minwidth pct    skip frames smaller than pct%
  --reverse         generate stack-reversed FlameGraph / Call tree

  --loop time       run profiler in a loop
  --alloc bytes     allocation profiling interval in bytes
  --live            build allocation profile from live objects only
  --lock duration   lock profiling threshold in nanoseconds
  --total           accumulate the total value (time, bytes, etc.)
  --all-user        only include user-mode events
  --sched           group threads by scheduling policy
  --cstack mode     how to traverse C stack: fp|dwarf|lbr|no
  --begin function  begin profiling when function is executed
  --end function    end profiling when function is executed
  --ttsp            time-to-safepoint profiling
  --jfrsync config  synchronize profiler with JFR recording
  --lib path        full path to libasyncProfiler.so in the container
  --fdtransfer      use fdtransfer to serve perf requests
                    from the non-privileged target

<pid> is a numeric process ID of the target JVM
      or 'jps' keyword to find running JVM automatically
      or the application's name as it would appear in the jps tool

Example: ./profiler.sh -d 30 -f profile.html 3456
         ./profiler.sh start -i 999000 jps
         ./profiler.sh stop -o flat jps
         ./profiler.sh -d 5 -e alloc MyAppName

--- Execution profile ---
Total samples       : 2189

--- 12710254800 ns (58.06%), 1271 samples
  [ 0] libmCos
  [ 1] Hello.for_loop
  [ 2] Hello.loopbig
  [ 3] Hello.main

--- 5710052600 ns (26.08%), 571 samples
  [ 0] libmSin
  [ 1] Hello.for_loop
  [ 2] Hello.loopbig
  [ 3] Hello.main

--- 1859944300 ns (8.50%), 186 samples
  [ 0] libmCos
  [ 1] Hello.for_loop
  [ 2] Hello.loopsmall
  [ 3] Hello.main

--- 760076900 ns (3.47%), 76 samples
  [ 0] libmSin
  [ 1] Hello.for_loop
  [ 2] Hello.loopsmall
  [ 3] Hello.main

--- 699998700 ns (3.20%), 70 samples
  [ 0] Hello.for_loop
  [ 1] Hello.loopbig
  [ 2] Hello.main

--- 150021300 ns (0.69%), 15 samples
  [ 0] Hello.for_loop
  [ 1] Hello.loopsmall
  [ 2] Hello.main

          ns  percent  samples  top
  ----------  -------  -------  ---
 14570199100   66.56%     1457  libmCos
  6470129500   29.56%      647  libmSin
   850020000    3.88%       85  Hello.for_loop

sudo ./profiler.sh -d 30 18006

java -agentpath:/path/to/libasyncProfiler.so=start,event=cpu,file=profile.html ...

(1)使用启动命令附加探查器代理
(2)休眠 5 秒
(3)然后使用停止命令再次附加代理

-agentpath:/path/to/libasyncProfiler.so=start,event=cpu,alloc=2m,lock=10ms,file=profile.jfr

jps
9234 Jps
8983 Hello
asprof -d 30 -f /tmp/flamegraph.html 8983

import java.util.ArrayList;
import java.util.Random;
import java.util.UUID;

/**
 * <p>
 * 模拟热点代码
 *
 * @Author niujinpeng
 */
public class HotCode {

    private static volatile int value;

    private static Object array;

    public static void main(String[] args) {
        while (true) {
            hotmethod1();
            hotmethod2();
            hotmethod3();
            allocate();
        }
    }

    /**
     * 生成 6万长度的数组
     */
    private static void allocate() {
        array = new int[6 * 1000];
        array = new Integer[6 * 1000];
    }

    /**
     * 生成一个UUID
     */
    private static void hotmethod3() {
        ArrayList<String> list = new ArrayList<>();
        UUID uuid = UUID.randomUUID();
        String str = uuid.toString().replace("-", "");
        list.add(str);
    }

    /**
     * 数字累加
     */
    private static void hotmethod2() {
        value++;
    }

    /**
     * 生成一个随机数
     */
    private static void hotmethod1() {
        Random random = new Random();
        int anInt = random.nextInt();
    }
}

./profiler.sh -d 30 -o tree -f /tmp/tmp.html 19685

--- Execution profile ---
Total samples       : 1743534

--- 442711562304 bytes (49.58%), 864644 samples
  [ 0] int[]
  [ 1] AllocatingTarget.allocate
  [ 2] AllocatingTarget.run
  [ 3] java.lang.Thread.run

--- 441959922816 bytes (49.50%), 863176 samples
  [ 0] java.lang.Integer[]
  [ 1] AllocatingTarget.allocate
  [ 2] AllocatingTarget.run
  [ 3] java.lang.Thread.run

--- 4181196800 bytes (0.47%), 7975 samples
  [ 0] java.lang.Integer[]
  [ 1] AllocatingTarget.allocate
  [ 2] AllocatingTarget.run
  [ 3] java.lang.Thread.run

--- 4057464832 bytes (0.45%), 7739 samples
  [ 0] int[]
  [ 1] AllocatingTarget.allocate
  [ 2] AllocatingTarget.run
  [ 3] java.lang.Thread.run

       bytes  percent  samples  top
  ----------  -------  -------  ---
446769027136   50.04%   872383  int[]
446141119616   49.96%   871151  java.lang.Integer[]

./profiler.sh -d 60 -e alloc -f /tmp/20417.alloc.html 20417

./profiler.sh -e HotCode.allocate 19685