RFR (S) 8150463: StringConcat MH_INLINE_SIZED_EXACT should skip storage initialization

Aleksey Shipilev aleksey.shipilev at oracle.com
Thu Mar 24 07:31:29 UTC 2016

On 03/16/2016 11:13 AM, Aleksey Shipilev wrote:
> I'd like to improve our advanced String concat strategy,
> MH_INLINE_SIZED_EXACT, with skipping the storage initialization:
>   https://bugs.openjdk.java.net/browse/JDK-8150463
> Webrev:
>   http://cr.openjdk.java.net/~shade/8150463/webrev.01/
> Performance had improved, as planned:
>   http://cr.openjdk.java.net/~shade/8150463/perf.txt
> The rest of the difference against BC_SB strategy is code-generation
> quirks, to be addressed separately. We pay some price for a runtime
> final index check to strengthen against inadvertent bugs in
> concatenation code.
> This patch does not affect the String concatenation at this point,
> because we are still running with BC_SB strategy. I ran through
> java/lang/String jtregs to see if MH_INLINE_SIZED_EXACT works as
> expected. Therefore, I don't think this needs to wait for Jigsaw
> integration. But, it can also wait, no problem. I'll let Jigsaw folks to
> decide on integration timing.

Anyone? I have re-based and re-tested the patch after Jigsaw
integration, and it still works fine (the webrev identical):


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