RFR: 8378675: PPC64: increase instruction cache line size [v3]

[Richard Reingruber]

On Thu, 26 Feb 2026 13:23:04 GMT, David Briemann <dbriemann at openjdk.org> wrote:

>> Set the instruction cache line size for Power to 128 bytes.
>> 
>> Add functions to retrieve the data cache line size and instruction cache line size from the system (AIX & Linux).
>
> David Briemann has updated the pull request incrementally with one additional commit since the last revision:
> 
>   remove comments, fix comparison

src/hotspot/cpu/ppc/vm_version_ppc.cpp line 483:

> (failed to retrieve contents of file, check the PR for context)
The calculation seems to be 1*BytesPerInstWord to high.
The comments are more confusing then helpful. I'd drop them.

I'd suggest the following.

```c++
#if defined(ABI_ELFv2)
  const int code_size = (num_features + 1 /*blr*/) * BytesPerInstWord;
#else
  const int code_size = (num_features + 1 /*blr*/ + 6 /* fd */) * BytesPerInstWord;
#endif

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

PR Review Comment: https://git.openjdk.org/jdk/pull/29918#discussion_r2864172215