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  1. JDK
  2. JDK-8217244

Safepoint::begin include early prolog in time measurement

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      >> We also don't measure the early prolog with:
      >> 380 Universe::heap()->safepoint_synchronize_begin();
      >> 381
      >> 382 // By getting the Threads_lock, we assure that no threads are about to start or
      >> 383 // exit. It is released again in SafepointSynchronize::end().
      >> 384 Threads_lock->lock();
      >>
      >> I had a measurement there but it was never any time spent there, something to keep in mind at least.
      >
      > Oh. Can we (should we) move the call to RuntimeService::record_safepoint_begin() before these? I'd
      > imagine CollectedHeap::safepoint_synchronize_begin() might take a while in some implementations, and
      > Threads_lock acquisition can be contended as well. It's fine to make it in a separate issue to avoid
      > tainting this one with artificial "regression".

      Also consider moving RuntimeService::record_safepoint_end(); after:

        // Release threads lock, so threads can be created/destroyed again.
        Threads_lock->unlock();

        // Wake threads after local state is correctly set.
        _wait_barrier->disarm();

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              • Assignee:
                rehn Robbin Ehn
                Reporter:
                rehn Robbin Ehn
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