Details
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Type:
Enhancement
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Status: Closed
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Priority:
P4
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Resolution: Duplicate
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Affects Version/s: 8
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Fix Version/s: None
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Component/s: core-libs
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Labels:
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Subcomponent:
Description
As described in JDK-8227006 the addition of container support has slowed down the execution of Runtime.availableProcessors. By calling this function in its spin-loop waitingGet() can also suffer from a severe slowdown in performance.
spins = (Runtime.getRuntime().availableProcessors() > 1) ?
1 << 8 : 0; // Use brief spin-wait on multiprocessors
As we only care about >1 processors we can cache this value in a field. The only problem case would be a >1 to 1 transition which is an unlikely change. If it did occur it would only result in a small performance hit anyway.
This fix is only needed for 8u as 9 and later have different code due toJDK-8157522
spins = (Runtime.getRuntime().availableProcessors() > 1) ?
1 << 8 : 0; // Use brief spin-wait on multiprocessors
As we only care about >1 processors we can cache this value in a field. The only problem case would be a >1 to 1 transition which is an unlikely change. If it did occur it would only result in a small performance hit anyway.
This fix is only needed for 8u as 9 and later have different code due to
Attachments
Issue Links
- duplicates
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JDK-8227018 CompletableFuture should not call Runtime.availableProcessors on fast path
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- Resolved
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- relates to
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JDK-8157522 Performance improvements to CompletableFuture
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- Resolved
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JDK-8227006 [linux] Runtime.availableProcessors execution time increased by factor of 100
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- Resolved
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