[jdk17u-dev] RFR: 8283199: Linux os::cpu_microcode_revision() stalls cold startup

[Thomas Stuefe]

On Mon, 24 Oct 2022 09:23:07 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Unclean backport to fix the startup time regression.
> 
> The backport is not clean, because [JDK-8238161](https://bugs.openjdk.org/browse/JDK-8238161) is not present in JDK 17, and thus we have `fopen` instead of `os::fopen` in these hunks. I changed the code back to `fopen` to be consistent with the rest of JDK 17.
> 
> Verified the startup time improves, using the scripts from the issue.
> 
> 
> # Before
> real	0m0.042s
> real	0m0.043s
> real	0m0.043s
> 
> # After
> real	0m0.025s
> real	0m0.024s
> real	0m0.024s
> 
> 
> Additional testing:
>  - [x] Linux x86_64 fastdebug `tier1`

All good.

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

Marked as reviewed by stuefe (Reviewer).

PR: https://git.openjdk.org/jdk17u-dev/pull/820