RFR: 8352042: [leyden] Parallel precompilation

[Aleksey Shipilev]

On Fri, 14 Mar 2025 12:22:00 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> For simplicity reasons, our current precompilation code uses effectively single-threaded blocking compiles. Even for simple cases, this makes assembly phase remarkably long. This does not scale well. We need to do precompilations in parallel. 
> 
> Unfortunately, I haven't found a good way to check that all async compilations are completed, so I introduced a new one.
> 
> Additional testing:
>  - [x] Ad-hoc precompilation tests
>  - [x] Linux x86_64 server fastdebug, `runtime/cds`

$ ./run-leyden.sh 

# Before

Generated source code for 10001 classes and compiled them in 19221 ms
AOTConfiguration recorded: app.aotconf

real	0m20.195s
user	0m51.408s
sys	0m1.466s

Reading AOTConfiguration app.aotconf and writing AOTCache app.aot
AOTCache creation is complete: app.aot

real	0m25.396s  ; <--- no parallelism
user	0m25.212s
sys	0m0.696s


# After

Generated source code for 10001 classes and compiled them in 19320 ms
AOTConfiguration recorded: app.aotconf

real	0m20.228s
user	0m50.004s
sys	0m1.419s

Reading AOTConfiguration app.aotconf and writing AOTCache app.aot
AOTCache creation is complete: app.aot

real	0m3.672s   ; <--- 6.6x parallelism
user	0m24.634s
sys	0m0.715s

-------------

PR Comment: https://git.openjdk.org/leyden/pull/49#issuecomment-2724524224