RFR: 8334779: Test compiler/c1/CanonicalizeArrayLength.java is timing out [v2]

[Tobias Hartmann]

On Wed, 26 Jun 2024 02:33:25 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> The timeout is cause by running the test with `-Xcomp -XX:+VerifyOops -XX:+PatchALot`.
>> The test continuously deoptimize and recompile `java.lang.Throwable::<init>` method.
>> `-XX:+VerifyOops ` adds a lot of external addresses because it use ExternallAddress for error messages.
>> These messages are unique for each call to `verify_oop()` because they are constructed locally.
>> I reduced number of loop iteration by 10 to get reasonable execution time (2 mins instead of 20 mins) and got next data:
>> 
>> Without VerifyOops:
>>   External addresses table: 38 entries
>> 
>> With VerifyOops:
>>   External addresses table: 125922 entries
>> 
>> Looks like most of the time VM is spending to grow/reallocate big growable array added by [JDK-8333819](https://bugs.openjdk.org/browse/JDK-8333819).
>> Before that change these addresses were recorded locally in nmethod's relocation info. When nmethod was deoptimized, its relocation info was discarded together with nmethod.
>> 
>> Only on x86 we declared message address as ExternalAddress. Aarch64 uses movptr() to store address as simple pointer. ARM uses own InlineAddress with RelocInfo::none type of relocation. I verified other platforms: none is using ExternalAddress.
>> 
>> I suggest to use AddressLiteral with RelocInfo::none for x86. With that the global table is small even with -XX:+VerifyOops:
>> 
>>   External addresses table: 42 entries
>> 
>> 
>> Tested tier1,  run test with corresponding flags to verify that time is similar to before [JDK-8333819](https://bugs.openjdk.org/browse/JDK-8333819)
>
> Vladimir Kozlov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Use external_word_Relocation::spec_for_immediate() instead of relocInfo::none

Looks good as stop-the-gap solution. Do you think there are opportunities to improve the GrowableArray situation?

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Marked as reviewed by thartmann (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/19871#pullrequestreview-2142517052