Using Intel PT with JIT

Using Intel PT with JIT

[Roman Lozko]

Hi, I tried to use `perf record` with Intel PT but afterwards I can't
inject JIT dump to trace, `perf inject` says:

error, jitted code must be sampled with perf record -k 1
0x59d8 [0xb0]: failed to process type: 10 [Operation not permitted]

On the other hand, `-k 1` cannot be passed to `perf record`:

Cannot use clockid (-k option) with intel_pt

Is there a way to use Intel PT with jitted code? I am using perf
5.13.8, maybe it is already implemented in later versions?

Re: Using Intel PT with JIT

[Adrian Hunter]

On 11/07/23 16:54, Roman Lozko wrote:
> Hi, I tried to use `perf record` with Intel PT but afterwards I can't
> inject JIT dump to trace, `perf inject` says:
> 
> error, jitted code must be sampled with perf record -k 1
> 0x59d8 [0xb0]: failed to process type: 10 [Operation not permitted]
> 
> On the other hand, `-k 1` cannot be passed to `perf record`:
> 
> Cannot use clockid (-k option) with intel_pt
> 
> Is there a way to use Intel PT with jitted code? I am using perf
> 5.13.8, maybe it is already implemented in later versions?
> 

Seems to work:

$ cat HelloWorldApp.java  
import java.util.*;

/**
* The HelloWorldApp class implements an application that
* simply prints "Hello World!" to standard output.
*/
class HelloWorldApp {
       public static void main(String[] args) {
               System.out.println("Hello World!"); // Display the string.
       }
}
$ javac HelloWorldApp.java
$ perf version
perf version 5.13.8.g3cfdd7252e00
$ perf record  -e intel_pt//u -o java.perf.data java -agentpath:/home/ahunter/git/linux-stable/tools/perf/libperf-jvmti.so HelloWorldApp  
java: jvmti: jitdump in /home/ahunter/.debug/jit/java-jit-20230711.XXgKfxna/jit-75025.dump
Hello World!
[ perf record: Woken up 3 times to write data ]
[ perf record: Captured and wrote 4.072 MB java.perf.data ]
$ perf inject -i java.perf.data --jit -o java.perf.data.jitted                                                                              
$