Integrated: 8368465: [leyden] Improve precompiler method selection code

[Aleksey Shipilev]

On Tue, 23 Sep 2025 12:33:23 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Forked from [JDK-8366681](https://bugs.openjdk.org/browse/JDK-8366681): there are still some cleanups/performance improvements possible. Current selection code is a bit hairy, and turns out the changes I made for previous patch improve performance.
> 
> Notable improvements:
>  1. Push the compilation level filters downwards. This allows compiling A2 from T2/T3 code more easily, and allows to implement policies for compiling on any A* level based on observing top-compiled T* levels.
>  2. Sort methods by hotness and code size. This looks to have a positive effect on shorter workloads, I suspect because we are avoiding a lot of C1 compilations by preloading hottest code first.
> 
> Additional testing:
>  - [x] Performance tests (see comments)
>  - [x] Linux x86_64 server fastdebug, `runtime/cds`

This pull request has now been integrated.

Changeset: 9c83531e
Author:    Aleksey Shipilev <shade at openjdk.org>
URL:       https://git.openjdk.org/leyden/commit/9c83531e88020f5762116020bcf472511058cffd
Stats:     99 lines in 2 files changed: 39 ins; 27 del; 33 mod

8368465: [leyden] Improve precompiler method selection code

Reviewed-by: kvn

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PR: https://git.openjdk.org/leyden/pull/99