RFR: 8234735: InstanceKlass:find_method_index regression after JDK-8231610

[coleen.phillimore at oracle.com]

+1
Coleen

On 11/25/19 1:50 PM, Ioi Lam wrote:
> Hi Claes,
>
> This change looks good to me.
>
> Thanks!
> - Ioi
>
> On 11/25/19 5:51 AM, Claes Redestad wrote:
>> Hi,
>>
>> JDK-8231610 refactored InstanceKlass::binary_search to ::quick_search,
>> which now has a linear slow-path version in case the VM is currently
>> dumping the dynamic CDS archive. This cause the methods to grow enough
>> that ::quick_search is not inlined into find_method_index, which cause a
>> local regression.
>>
>> Since the linear search is not as performance sensitive as the default
>> binary search, then outlining the slow-path to a different method makes
>> sense. Tests show that this allows the performance critical path to be
>> completely inlined again, recuperating about half of the performance
>> regression (still adds a branch to check for whether we should do a
>> linear search to the fast path, compared to pre-8231610)
>>
>> Bug:    https://bugs.openjdk.java.net/browse/JDK-8234735
>> Webrev: http://cr.openjdk.java.net/~redestad/8234735/open.00/
>>
>> Testing: tier1-3
>>
>> Thanks!
>>
>> /Claes
>