RFR: 8291550: RISC-V: jdk uses misaligned memory access when AvoidUnalignedAccess enabled [v8]

[Vladimir Kempik]

On Fri, 5 May 2023 12:51:37 GMT, Feilong Jiang <fjiang at openjdk.org> wrote:

>> If I remember correctly, there are some misaligned access at string intrinsics. Here are the related PRs at riscv-collab:
>> 
>> - https://github.com/riscv-collab/riscv-openjdk/pull/19
>> - https://github.com/riscv-collab/riscv-openjdk/pull/17
>> - https://github.com/riscv-collab/riscv-openjdk/pull/14
>
>> @feilongjiang , do you know any reason why first two (string_equals & string_compare) wasn't ever integrated ?
> 
> At that time, we were focused on upstreaming the risc-v port. The misaligned access issues for those intrinsics are not a high priority. So we just reverted string_equals changes, and string_compare was closed before being integrated.

@feilongjiang 
I have applied your patch for string_equals, and now amount of trp_lam event is very low ( about a dozen)
mostly coming from
        Thread-2 43606 851688.227592:          1 trp_lam:        3f88c5e4aa JVM_handle_linux_signal+0xee (/home/vkempik/syntaj/lib/server/libjvm.so)


Would you open a new PR with string_equals patch ? or I can just add that patch into this PR

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PR Comment: https://git.openjdk.org/jdk/pull/13645#issuecomment-1537078953