RFR: 8242959: Optimize ZipFile.getEntry by folding lookups for name and name+'/'

[Claes Redestad]

Hi Lance,

thank you for reviewing!

/Claes

On 2020-04-17 17:23, Lance Andersen wrote:
> HI Claes,
> 
> I think this looks good.
> 
> Best
> Lance
> 
>> On Apr 17, 2020, at 7:33 AM, Claes Redestad <claes.redestad at oracle.com 
>> <mailto:claes.redestad at oracle.com>> wrote:
>>
>> Hi,
>>
>> please review this patch to get rid of the back-to-back lookup of name
>> and name+'/' in ZipFile.getEntry. This is done by first adjusting the
>> hash function so that a trailing slash is not included in an entry's
>> hash code, and adjusting appropriately when matching the arrays.
>>
>> This means we do fewer table lookups, less arithmetic and potentially
>> less allocation on lookup misses.
>>
>> Patch contributed by Eirik Bjørsnøs.
>>
>> Webrev: http://cr.openjdk.java.net/~redestad/8242959/open.00/
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8242959
>>
>> Testing: tier1+2, verified neutral performance for hits and a
>> significant reduction in cost of misses (~30-50ms improvement on
>> Spring PetClinic startup).
>>
>> Thanks!
>>
>> /Claes
> 
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