Integrated: 8331187: Optimize MethodTypeDesc and ClassDesc.ofDescriptor for primitive types

[Claes Redestad]

On Fri, 26 Apr 2024 10:27:16 GMT, Claes Redestad <redestad at openjdk.org> wrote:

> This PR makes ClassDesc.ofDescriptor return the shared constant for primitive descriptor strings ("I" etc..), and leverages this further by refactoring `MethodTypeDescImpl.ofDescriptor` to avoid the intermediate substring for primitives. 
> 
> Microbenchmarks results look good with expected speedups and allocation reductions any time a primitive is part of the descriptor string, and a non-significant cost otherwise:
> 
> 
> Name                                                             (descString) Cnt     Base     Error       Test     Error   Unit  Change
> ClassDescFactories.ofDescriptor                            Ljava/lang/Object;   6   13,941 ±   1,643     14,071 ±   1,333  ns/op   0,99x (p = 0,681 )
>   :gc.alloc.rate.norm                                                               16,000 ±   0,000     16,000 ±   0,000   B/op   1,00x (p = 0,617 )
> ClassDescFactories.ofDescriptor                                             V   6    9,212 ±   1,045      1,405 ±   0,049  ns/op   6,55x (p = 0,000*)
>   :gc.alloc.rate.norm                                                               48,000 ±   0,000      0,000 ±   0,000   B/op   0,00x (p = 0,000*)
> ClassDescFactories.ofDescriptor                                             I   6    9,009 ±   0,035      1,431 ±   0,192  ns/op   6,30x (p = 0,000*)
>   :gc.alloc.rate.norm                                                               48,000 ±   0,000      0,000 ±   0,000   B/op   0,00x (p = 0,000*)
> MethodTypeDescFactories.ofDescriptor  (Ljava/lang/Object;Ljava/lang/String;)I   6  182,050 ±   4,333    141,644 ±   2,685  ns/op   1,29x (p = 0,000*)
>   :gc.alloc.rate.norm                                                              360,001 ±   0,000    264,001 ±   0,000   B/op   0,73x (p = 0,000*)
> MethodTypeDescFactories.ofDescriptor                                      ()V   6   17,169 ±   2,008      9,915 ±   0,018  ns/op   1,73x (p = 0,000*)
>   :gc.alloc.rate.norm                                                              120,000 ±   0,000    104,000 ±   0,000   B/op   0,87x (p = 0,000*)
> MethodTypeDescFactories.ofDescriptor ([IJLjava/lang/String;Z)Ljava/util/List;   6  270,372 ±   3,624    217,050 ±   3,170  ns/op   1,25x (p = 0,000*)
>   :gc.alloc.rate.norm                                                              520,002 ±   0,000    328,001 ±   0,000   B/op   0,63x (p = 0,000*)
> MethodTypeDescFactories.ofDescriptor                    ()[Ljava/lang/String;   6   35,036 ±   0,351     36,010 ±   3,882  ns/op   0,97x (p = 0,1...

This pull request has now been integrated.

Changeset: 8bbd7251
Author:    Claes Redestad <redestad at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/8bbd7251a596c6fad1a6675c077deb9fd7c8ff95
Stats:     140 lines in 6 files changed: 87 ins; 19 del; 34 mod

8331187: Optimize MethodTypeDesc and ClassDesc.ofDescriptor for primitive types

Reviewed-by: jvernee, liach

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PR: https://git.openjdk.org/jdk/pull/18971