On Thu, 30 Mar 2023 17:10:16 GMT, Serguei Spitsyn <[email protected]> wrote:
>> The fix is to enable virtual threads support for late binding JVMTI agents.
>> The fix includes:
>> - New function `JvmtiEnvBase::enable_virtual_threads_notify_jvmti()` which
>> does enabling JVMTI VTMS transition notifications in case of agent loaded
>> into running VM. This function executes a VM operation counting VTMS
>> transition bits in all `JavaThread`'s to correctly set the static counter
>> `_VTMS_transition_count` needed for VTMS transition protocol.
>> - New function `JvmtiEnvBase::disable_virtual_threads_notify_jvmti()` which
>> is needed for testing. It is used by the `WhiteBox` API.
>> - New WhiteBox function `WB_SetVirtualThreadsNotifyJvmtiMode(JNIEnv* env,
>> jobject wb, jboolean enable)` needed for testing of this update.
>> - New regression test: `serviceability/jvmti/vthread/ToggleNotifyJvmtiTest`
>>
>> Testing:
>> - New test: `serviceability/jvmti/vthread/ToggleNotifyJvmtiTest`
>> - The originally failed tests are expected to pass now:
>> `runtime/vthread/RedefineClass.java`
>> `runtime/vthread/TestObjectAllocationSampleEvent.java`
>> - In progress: Run the tiers 1-6 to make sure there are no regression.
>
> Serguei Spitsyn has updated the pull request incrementally with one
> additional commit since the last revision:
>
> review: tweak in count_transitions_and_correct_jvmti_thread_states
test/hotspot/jtreg/serviceability/jvmti/vthread/ToggleNotifyJvmtiTest/ToggleNotifyJvmtiTest.java
line 45:
> 43: // to have sleep() calls to provide yielding as some frequency of virtual
> 44: // thread mount state transitions is needed for this test scenario.
> 45: class TestedThread extends Thread {
Shouldn't this be a Runnable instead of a Thread? I would also suggest not
using the term "thread" here. Maybe "task"? Otherwise code like the following
is misleading:
TestedThread thread = threads[i];
thread.letFinish();
There are no threads being referenced in this code, yet the term "thread" is
used 4 times.
test/hotspot/jtreg/serviceability/jvmti/vthread/ToggleNotifyJvmtiTest/ToggleNotifyJvmtiTest.java
line 170:
> 168: // Disable notifyJvmti events mode at test cycle start.
> 169: // It is unsafe to do so if any virtual threads are executed.
> 170: setVirtualThreadsNotifyJvmtiMode(iter, false);
What happens if the main thread is a virtual thread because the virtual thread
wrapper is being used? Is there any concern with disabling notifications in
this case?
test/hotspot/jtreg/serviceability/jvmti/vthread/ToggleNotifyJvmtiTest/ToggleNotifyJvmtiTest.java
line 172:
> 170: setVirtualThreadsNotifyJvmtiMode(iter, false);
> 171:
> 172: Thread tt =
> Thread.ofPlatform().name("StartThreadsTest").start(ToggleNotifyJvmtiTest::startThreads);
Why does each test cycle need to be run in a separate platform thread? Can't
you just use the main test thread?
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/13133#discussion_r1153845337
PR Review Comment: https://git.openjdk.org/jdk/pull/13133#discussion_r1153850702
PR Review Comment: https://git.openjdk.org/jdk/pull/13133#discussion_r1153849125
