RFR: 8260355: AArch64: deoptimization stub should save vector registers [v4]

[Andrew Haley]

On 2/4/21 7:21 AM, Nick Gasson wrote:
> On 02/03/21 17:36 pm, Andrew Haley wrote:
>>>
>>> @theRealAph are the sharedRuntime_aarch64.cpp changes ok?
>>
>> I guess so, but the code changes are so complex and delicate it's extremely
>> hard to tell.
>>
>> What have you done about stress testing? I guess we need some code that's
>> repeatedly deoptimized and recompiled millions of times, with continuous
>> testing. I guess that in order to make sure nothing has regressed, a
>> bootstrap with DeoptimizeALot would help gain some confidence.
> 
> I tried make bootcycle-images as you suggest with -XX:+DeoptimizeALot
> added to JAVA_FLAGS and JAVA_FLAGS_BIG in bootcycle-spec.gmk.in (not
> sure if there's a better way to do that...).
> 
> I've also previously run the tier1 and java/incubator/vector/* tests
> with -XX:+DeoptimizeALot. My experience of modifying that code is that
> DeoptimizeALot fails pretty quickly if you get something wrong.

Yeah. The problem here is that safepoints with live vectors aren't so
common, so it's hard to test, I get it. Maybe this will have to do.

-- 
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
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