On Thu, 8 Aug 2024 20:06:08 GMT, Chris Plummer <cjplum...@openjdk.org> wrote:
>> JVMTI has a somewhat unique event called DataDumpRequest. One way it is
>> triggered is via the JVMTI.data_dump jcmd, which causes JVMTI to send the
>> DataDumpRequest event to all agents that have registered for the event
>> callback. The agent is free to do pretty much what it wants during the
>> callback, but the normal usage is to dump anything that might be useful for
>> debugging the agent. In the case of the debug agent, it could dump internal
>> data like the list of known threads and event handlers. After ranked monitor
>> support is complete, it can also dump the state of all jvmti raw monitors
>> that the debug agent uses.
>>
>> I decided to not enable this feature by default, and not make public the
>> option to enable it. This should only be used by developers working on the
>> debug agent, or by users when requested to do so (by debug agent developers)
>> to help debug a debug agent problem.
>>
>> Most of the code executed during the data dump was only available for debug
>> builds, so I've made it available for all builds. Their addition does not
>> affect product builds except for adding a small footprint.
>>
>> TBD is directing the output to a file. This is useful for some of the
>> debugger tests that don't include the debuggee output in the log. This seems
>> to be the case for most com/sun/jdi tests. I decided not to include it for
>> this first pass since it is rather disruptive and detracts from the main
>> changes being made.
>>
>> testing tbd: run all tier1, tier2, and. tie5 svc tests.
>
> Chris Plummer has updated the pull request incrementally with one additional
> commit since the last revision:
>
> Improved comments.
FYI, this is what the (entire) debuggee output looks like for this test:
Deuggee output:
Listening for transport dt_socket at address: 42509
Debug Agent Data Dump
=== START DUMP ===
suspendAllCount: 0
Dumping runningThreads:
Thread: node = 0x149684000f10, jthread = 0x1497504da382
name: Notification Thread
suspendCount: 0
Thread: node = 0x14969c000f10, jthread = 0x1497504da352
name: Common-Cleaner
suspendCount: 0
Thread: node = 0x149750583a60, jthread = 0x1497504da332
name: Attach Listener
suspendCount: 0
Thread: node = 0x1497505835c0, jthread = 0x1497504da32a
name: Signal Dispatcher
suspendCount: 0
Thread: node = 0x149750583120, jthread = 0x1497504da322
name: Finalizer
suspendCount: 0
Thread: node = 0x149750582c50, jthread = 0x1497504da31a
name: Reference Handler
suspendCount: 0
Thread: node = 0x1497505827b0, jthread = 0x1497504da312
name: main
suspendCount: 1
Dumping runningVThreads:
Dumping otherThreads:
Handlers for EI_CLASS_PREPARE(7)
node(0x1496a40034e0) handlerID(4) suspendPolicy(1) permanent(0)
ClassMatch: classPattern(DataDumpTestTarg)
node(0x1496a4002d80) handlerID(2) suspendPolicy(0) permanent(0)
Handlers for EI_CLASS_UNLOAD(8)
node(0x1496a4002de0) handlerID(3) suspendPolicy(0) permanent(0)
Handlers for EI_VM_DEATH(20)
node(0x1496a4004a20) handlerID(0) suspendPolicy(0) permanent(1)
=== END DUMP ===
Debuggee started
-------------
PR Comment: https://git.openjdk.org/jdk/pull/20367#issuecomment-2276641888
