On Mon, 5 Jun 2023 18:52:00 GMT, Doug Lea <d...@openjdk.org> wrote: > This update addresses performance issues across both LinkedTransferQueue and > SynchronousQueue by creating a common basis for implementation across them > (mainly in LinkedTransferQueue). Pasting from internal doc summary of > changes: > * * Class DualNode replaces Qnode, with fields and methods > * that apply to any match-based dual data structure, and now > * usable in other j.u.c classes. in particular, SynchronousQueue. > * * Blocking control (in class DualNode) accommodates > * VirtualThreads and (perhaps virtualized) uniprocessors. > * * All fields of this class (LinkedTransferQueue) are > * default-initializable (to null), allowing further extension > * (in particular, SynchronousQueue.Transferer) > * * Head and tail fields are lazily initialized rather than set > * to a dummy node, while also reducing retries under heavy > * contention and misorderings, and relaxing some accesses, > * requiring accommodation in many places (as well as > * adjustments in WhiteBox tests).
This pull request has now been integrated. Changeset: 8d1ab570 Author: Doug Lea <d...@openjdk.org> URL: https://git.openjdk.org/jdk/commit/8d1ab57065c7ebcc650b5fb4ae098f8b0a35f112 Stats: 1714 lines in 3 files changed: 331 ins; 930 del; 453 mod 8301341: LinkedTransferQueue does not respect timeout for poll() 8300663: java/util/concurrent/SynchronousQueue/Fairness.java failed with "Error: fair=true i=0 j=1" 8267502: JDK-8246677 caused 16x performance regression in SynchronousQueue Reviewed-by: alanb ------------- PR: https://git.openjdk.org/jdk/pull/14317
