Created
December 25, 2019 21:38
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JDK 14 - Project Loom virtual threads (ex-fibers) test - CAS vs LongAdder performance comparison
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(ns me.core | |
(:import [java.util.concurrent.atomic LongAdder] | |
[java.util.concurrent CountDownLatch])) | |
(defmacro fiber [& body] | |
`(.. (Thread/builder) | |
(virtual) | |
(task (fn [] ~@body)) | |
; (build) | |
(start))) | |
(time | |
(let [c (atom 0) | |
n (int 1e8)] | |
(dotimes [_ n] | |
(swap! c inc)) | |
@c)) | |
;; thread contention - ~10 times slower than 1 thread | |
(time | |
(let [s (atom 0) | |
n (int 100) | |
doneSignal (CountDownLatch. n)] | |
(dotimes [_ n] | |
(fiber | |
(dotimes [_ 1e6] (swap! s inc)) | |
(.countDown doneSignal))) | |
(.await doneSignal) | |
@s)) | |
(time | |
(let [a (LongAdder.) | |
n (long 1e8)] | |
(dotimes [_ n] | |
(.increment a)) | |
(.sum a))) | |
;; non-blocking LongAdder - nice! - ~6 times faster on 4 cores than 1 thread | |
(let [a (LongAdder.) | |
n-threads (int 1000) | |
startSignal (CountDownLatch. 1) | |
doneSignal (CountDownLatch. n-threads)] | |
(dotimes [_ n-threads] | |
(let [t (fiber (do | |
(.await startSignal) | |
(dotimes [_ 100000] (.increment a)) | |
(.countDown doneSignal)))] | |
t)) | |
(time (do | |
(.countDown startSignal) | |
(.await doneSignal) | |
(.sum a)))) |
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