Skip to content

Latest commit

 

History

History
 
 

first_example_ipc

README.md

Basic example of standalone jbpf operation

This example showcases a basic jbpf usage scenario, when using in IPC mode. It provides a C++ application (example_collect_control) that initializes jbpf in IPC primary mode, a dummy C++ application (example_app), that initializes jbpf in IPC secondary mode, and an example codelet (example_codelet.o). The example demonstrates the following:

  1. How to declare and call hooks in the jbpf secondary process.
  2. How to collect data sent by the codelet from the jbpf primary process.
  3. How to load and unload codeletsets using the LCM CLI tool (via a Unix socket API).
  4. How to send data back to running codelets from the jbpf primary process.

For more details of the exact behavior of the application and the codelet, you can check the inline comments in example_collect_control.cpp, example_app.cpp and example_codelet.c

Usage

This example expects jbpf to be built.

To build the example from scratch, we run the following commands:

$ source ../../setup_jbpf_env.sh
$ make

This should produce the binaries example_collect_control, example_app and example_codelet.o.

To bring the primary application up, we run the following commands:

$ source ../../setup_jbpf_env.sh
$ ./run_collect_control.sh

If successful, we shoud see the following line printed:

[JBPF_INFO]: Allocated size is 1107296256

To bring the primary application up, we run the following commands on a second terminal:

$ source ../../setup_jbpf_env.sh
$ ./run_app.sh

If successful, we shoud see the following printed in the log of the secondary:

[JBPF_INFO]: Agent thread initialization finished
[JBPF_INFO]: Setting the name of thread 1035986496 to jbpf_lcm_ipc
[JBPF_INFO]: Registered thread id 1
[JBPF_INFO]: Started LCM IPC thread at /var/run/jbpf/jbpf_lcm_ipc
[JBPF_DEBUG]: jbpf_lcm_ipc thread ready
[JBPF_INFO]: Registered thread id 2
[JBPF_INFO]: Started LCM IPC server

and on the primary:

[JBPF_INFO]: Negotiation was successful
[JBPF_INFO]: Allocation worked for size 1073741824
[JBPF_INFO]: Allocated size is 1073741824
[JBPF_INFO]: Heap was created successfully

To load the codeletset, we run the following commands on a third terminal window:

$ source ../../setup_jbpf_env.sh
$ ./load.sh

If the codeletset was loaded successfully, we should see the following output in the example_app window:

[JBPF_INFO]: VM created and loaded successfully: example_codelet

After that, the primary example_collect_control should start printing periodical messages (once per second):

{
    "seq_no": "2",
    "value": "-2",
    "name": "instance 2"
}

Similarly, the secondary example_app should also print periocical messages:

[JBPF_DEBUG]:  Called 2 times so far and received response for seq_no 2

To unload the codeletset, we run the command:

$ ./unload.sh

The example_app should stop printing the periodical messages and should give the following output:

[JBPF_INFO]: VM with vmfd 0 (i = 0) destroyed successfully