RFR: 8365053: Refresh hotspot precompiled.hpp with headers based on current frequency [v10]

[Magnus Ihse Bursie]

On Fri, 8 Aug 2025 06:32:57 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

>> Francesco Andreuzzi has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - magic number: 400
>>  - inline
>
> src/hotspot/share/precompiled/precompiled.hpp line 70:
> 
>> 68: #include "utilities/ticks.hpp"
>> 69: 
>> 70: #ifdef TARGET_COMPILER_visCPP
> 
> All of the reported testing was on Linux. These were included specifically because measurements
> said their inclusion here was beneficial. And my recollection from previous discussions is that
> Visual Studio may be the compiler where precompiled headers are most beneficial.

Indeed, Visual Studio is the place where PCH is most needed. I see Erik says he tested on Windows with no difference. While he concluded that this means no regression, I see it as a missed opportunity. Giving the Windows platform a bit of extra love can probably increase compilation speed where it is needed the most.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26681#discussion_r2265948776