On Mon, 13 Oct 2025 19:53:27 GMT, Chen Liang <[email protected]> wrote:
> There's a spike of calls to `Unsafe.isFlatField` in serialzation workloads. > The layout information can be prepared with FieldReflector and cached. CI > looks good, need to verify the regression is fixed. > > The old perfasm profile was: > ....[Hottest > Regions]............................................................................... > 4.66% libjvm.so Unsafe_IsFlatField > 4.13% c2, level 4 java.io.ObjectOutputStream::writeObject0, version 6, > compile id 2698 > 3.72% c2, level 4 > java.io.ObjectInputStream$BlockDataInputStream::readUTFSpan, version 2, > compile id 1878 > 3.61% c2, level 4 java.io.ObjectInputStream$PeekInputStream::readFully, > version 2, compile id 1902 I don't think FieldLayout is sufficient for the long term - I view this array polymorphism as a baby step towards a polymorphic VM. What should replace an int layout should be a specialization anchor in the long run. ------------- PR Comment: https://git.openjdk.org/valhalla/pull/1676#issuecomment-3407229026
