Performance degradation with 3.0.1(String comparison)


(Pushkar N Kulkarni) #1

Hello,

A colleague of mine who’s doing performance testing with some server-side Swift frameworks like Kitura, Perfect and Zewo found a 15-20% degradation with a simple “Hello World” benchmark, with the 3.0.1 previews on Linux. Analysis revealed it is related to the disabling of an optimisation around String comparison for Swift runtimes - this commit - apple/swift@ef974af

Thank you!

Pushkar N Kulkarni,

IBM Runtimes

Simplicity is prerequisite for reliability - Edsger W. Dijkstra

Do we have a plan to reimplement this optimisation for Swift runtimes in the future? Any more information about this would be highly appreciated.


(Michael Gottesman) #2

Hello,

A colleague of mine who's doing performance testing with some server-side Swift frameworks like Kitura, Perfect and Zewo found a 15-20% degradation with a simple "Hello World" benchmark, with the 3.0.1 previews on Linux. Analysis revealed it is related to the disabling of an optimisation around String comparison for Swift runtimes - this commit - apple/swift@ef974af <https://github.com/apple/swift/commit/ef974af339996f63c72d54ec7ef53b625e5a1a76>

Do we have a plan to reimplement this optimisation for Swift runtimes in the future? Any more information about this would be highly appreciated.

Can you please provide a benchmark in a pull request that shows the performance degradation?

Michael

···

On Nov 3, 2016, at 11:07 PM, Pushkar N Kulkarni via swift-dev <swift-dev@swift.org> wrote:

Thank you!

Pushkar N Kulkarni,
IBM Runtimes

Simplicity is prerequisite for reliability - Edsger W. Dijkstra

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