JDK-8153189 : Release Note: Implemented performance improvements for BigInteger.montgomeryMultiply
  • Type: Sub-task
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 7u97,7u111,8u77,8u102,9
  • Priority: P4
  • Status: Closed
  • Resolution: Delivered
  • Submitted: 2016-03-31
  • Updated: 2022-06-14
  • Resolved: 2017-02-13
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JDK 7 JDK 8 JDK 9
7u111Resolved 8u102Resolved 9Resolved
Description
We have implemented improvements that will improve performance of several security algorithms, especially when using ciphers with key lengths of 2048-bit or greater. To turn on these improvements, use the options -XX:+UseMontgomeryMultiplyIntrinsic and -XX:+UseMontgomerySquareIntrinsic. This improvement is only for Linux and Solaris on x86_64 architecture.
Comments
It's no more than caution. On 09.03.2016 16:41, Seán Coffey wrote: > Apologies for the delay. This is now approved for jdk8u-dev but with a > caveat. The quality team are concerned with putting such a change into > the update releases. For the short term, let's put the new features > behind a flag and let's have the new feature off by default. Such > intrinsics flags already exist in the hotspot code. > > I'd suggest that you push the code as is and follow up with the > default flag change in a separate bug ID. I would ask that both > 8081778 and 8130150 enhancements be off by default. We can document > how to switch them on. Once enough testing is done, they should be > switched on by default (in a later update release)
24-05-2017
Both the release notes and this bug include no description of why the improved behaviour is only available via a configuration switch. Tradeoffs? Eventual default? More tunable switches is NOT what OpenJDK needs. (unless you are a JVM tuning consultant...)
20-07-2016
Minor text change in the description, from: 2048-bit or bigger To: 2048-bit or greater
16-05-2016