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  1. JDK
  2. JDK-8227018

CompletableFuture should not call Runtime.availableProcessors on fast path

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        In 8u, CompletableFuture calls Runtime.availableProcessors during spin in waitingGet:

            private Object waitingGet(boolean interruptible) {
        ...
                while ((r = result) == null) {
                    if (spins < 0)
                        spins = (Runtime.getRuntime().availableProcessors() > 1) ?
                            1 << 8 : 0; // Use brief spin-wait on multiprocessors

        Unfortunately, that falls victim to JDK-8227006, which makes it too costly. This is fixed in 9 with JDK-8134851, but that patch is too large and intrusive to backport to 8u. Therefore, we should consider backporting the small part of that patch that deals with availableProcessors handling.

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            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8228423 CompletableFuture should not call Runtime.availableProcessors on fast path

            • P3 - Major loss of function.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8235031 CompletableFuture should not call Runtime.availableProcessors on fast path

            • P3 - Major loss of function.
            • Resolved
            duplicates

            Enhancement - null JDK-8227019 CompletableFuture.waitingGet shouldn't call Runtime.availableProcessors in a tight loop

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Closed
            relates to

            Sub-task - The sub-task of the issue JDK-8134851 Integrate CompletableFuture with API enhancements

            • P2 - Crashes, loss of data, severe memory leak.
            • Resolved

            Bug - A problem which impairs or prevents the functions of the product. JDK-8227006 [linux] Runtime.availableProcessors execution time increased by factor of 100

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

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                shade Aleksey Shipilev
                shade Aleksey Shipilev
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                  Created:
                  Updated:
                  Resolved: