[omworld-jdk] RFR: 8326752: Lilliput: OMCache: Add cache lookup unrolling [v3]

[Roman Kennke]

On Tue, 27 Feb 2024 12:43:04 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

>> Implement unrolling of OM cache lookups in C2 so experiments and an evaluation can be performed.
>> 
>> Adds `OMC2UnrollCacheLookup`, `OMC2UnrollCacheLookupLoopTail` and `OMC2UnrollCacheEntires` flags which can be tuned cache lookup unrolling in C2. 
>> 
>> `OMC2UnrollCacheLookup` will unroll up to `OMC2UnrollCacheEntires` (depending on `OMCacheSize`) and if `OMC2UnrollCacheLookupLoopTail` is set and entries are left the rest of the cache will be checked.
>> 
>> All of these flags are temporary to allow for evaluation of the cache lookup in C2 (size and unrolling). See issue JDK-8326759
>
> Axel Boldt-Christmas has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Remove OMC2UnrollCacheLookup flag

Looks good! Thank you!

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Marked as reviewed by rkennke (Reviewer).

PR Review: https://git.openjdk.org/lilliput/pull/139#pullrequestreview-1903440661