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List:       openjdk-hotspot-runtime-dev
Subject:    Re: RFR: 8234735: InstanceKlass:find_method_index regression after JDK-8231610
From:       Ioi Lam <ioi.lam () oracle ! com>
Date:       2019-11-25 18:50:24
Message-ID: 994ada01-e1ee-e7bd-6a3f-9c1a8136684f () oracle ! com
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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

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