RFR: 8317542: Specjvm::xml have scalability issue for high vCPU numbers [v2]

[Alan Bateman]

On Thu, 7 Nov 2024 16:42:55 GMT, Vladimir Ivanov <vaivanov at openjdk.org> wrote:

>> The synchronization block may be substituted by the 'volatile' variable smaller synchronization block.
>> It reduce the total blocking time for the specjvm2008::xml.validation workload and improve the reported score.
>> Scores for the 112vCPU on the with 28GB heap increased from 17915.83 to 22943.2.
>> Unit tests was not affected:
>> Test summary
>> ==============================
>>    TEST                                              TOTAL  PASS  FAIL ERROR
>>    jtreg:test/jaxp                                     516   516     0     0
>>    jtreg:test/jdk/javax/xml                             70    70     0     0
>> ==============================
>> TEST SUCCESS
>> 
>> The tier1 is OK too.
>
> Vladimir Ivanov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8317542: Specjvm::xml have scalability issue for high vCPU numbers

src/java.xml/share/classes/com/sun/org/apache/xerces/internal/impl/xpath/regex/RegularExpression.java line 2019:

> 2017:         int length;
> 2018:         Match match;
> 2019:         private Semaphore inuse = new Semaphore(1, true);

Does it require fairness? The existing code using object monitors so I assume not. I assume "inuse" can be final.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21815#discussion_r1833031188