RFR: 8283199: Linux os::cpu_microcode_revision() stalls cold startup [v3]

[Aleksey Shipilev]

On Mon, 21 Mar 2022 12:58:21 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Partially revert the buffer trim
>
> src/hotspot/os_cpu/linux_x86/os_linux_x86.cpp line 467:
> 
>> 465: 
>> 466:   // Attempt 1 (faster): Read the microcode version off the sysfs.
>> 467:   {
> 
> Why the new block?

Because I don't want to extend the lifetime of `fp`, `data`, etc.

> src/hotspot/os_cpu/linux_x86/os_linux_x86.cpp line 482:
> 
>> 480: 
>> 481:   // Attempt 2 (slower): Read the microcode version off the procfs.
>> 482:   {
> 
> Why the new block?

Because there are plenty of locals that needs to be redefined: `fp`, `data` among others.

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

PR: https://git.openjdk.java.net/jdk/pull/7825