java flamegraph not complete

[datavisorhenryzhao]

Describe the bug
I deployed the pixie (self host), find the flame-graph is not complete

To Reproduce
Steps to reproduce the behavior:

1. Deploy pixie for k8s
   os: Ubuntu 22.04.3 LTS
   kernel: 6.2.0-1015-aws
   vizier-pem: gcr.io/pixie-oss/pixie-prod/vizier-pem_image:0.14.9
   java version

openjdk version "1.8.0-builds.shipilev.net-openjdk-shenandoah-jdk8-b798-20210222"
OpenJDK Runtime Environment (build 1.8.0-builds.shipilev.net-openjdk-shenandoah-jdk8-b798-20210222-testing-b00)
OpenJDK 64-Bit Server VM (build 25.71-b00, mixed mode)

3. Write java code

public class HelloWorld {
    public static void main(String[] args) {
        while (true) { 
                int i = 0;
                while (i < 1000000) {
                        f1();
                        i++;
                }
                try {
                // 暂停 5 毫秒
                        Thread.sleep(5);
                    } catch (InterruptedException e) {
                        System.out.println("Sleep was interrupted.");
                    }
        }
    }
    public static void f1() {
                try {
                // 暂停 5 毫秒
                        Thread.sleep(1);
                    } catch (InterruptedException e) {
                        System.out.println("Sleep was interrupted.");
                    }
        f2();
    }
    public static void f2() {
                try {
                // 暂停 5 毫秒
                        Thread.sleep(1);
                    } catch (InterruptedException e) {
                        System.out.println("Sleep was interrupted.");
                    }
        f3();
    }
    public static void f3() {
                try {
                // 暂停 5 毫秒
                        Thread.sleep(1);
                    } catch (InterruptedException e) {
                        System.out.println("Sleep was interrupted.");
                    }

    }

}

5. set entry point of the container image; and run in pod
   java -XX:+PreserveFramePointer HelloWorld

6. select the pod and lookup Flamegraph

but I can not see f1/f2/f3 symbol

App information (please complete the following information):

• Pixie version: gcr.io/pixie-oss/pixie-prod/vizier-pem_image:0.14.9
• K8s : 1.24
• Node Kernel version: 6.2.0-1015-aws
• Browser version: Chrome 131.0.6778.266

[datavisorhenryzhao]

I find only when i execute javac -g HelloWorld1.java, i can see the function f1(), by both the following cmd. So I think PreserveFramePointer have no effect

java -XX:+PreserveFramePointer HelloWorld1

java HelloWorld1

[ddelnano]

Hi @datavisorhenryzhao, thanks for the bug report.

Can you collect the PEM logs via px collect-logs while that workload is running? It would also be helpful (but not required) if you could add the following cli flag to the PEM DaemonSet before collecting the logs: --vmodule=px_jattach=1,perf_profile_connector=1,stringifier=1,elf_symbolizer=1

I will try to reproduce the issue on my own sometime this week as well, but having the logs would be very helpful.

[datavisorhenryzhao]

1. when compiled without '-g'

2.when compiled with '-g', can find f1 symbol, but f2/f3 not found

3. info of pem-pod(where pod henry runs with same node)

By the way how to add the flag for pem ds? Do you know the full args?
--vmodule=px_jattach=1,perf_profile_connector=1,stringifier=1,elf_symbolizer=1

pixie_logs_20250130110549.zip

I also tried parca project (based on ebpf), it shows the full java stack (f1/f2/f3) only when compiled with '-g'