[crac] RFR: Support -XX:CPUFeatures=ignore during -XX:CRaCRestoreFrom

[Radim Vansa]

On Wed, 9 Aug 2023 13:55:30 GMT, Jan Kratochvil <jkratochvil at openjdk.org> wrote:

> Support -XX:CPUFeatures=ignore during -XX:CRaCRestoreFrom

src/hotspot/cpu/x86/globals_x86.hpp line 229:

> 227:       "get an error during -XX:CRaCRestoreFrom on a different machine; "    \
> 228:       "-XX:CPUFeatures=native is the default; "                             \
> 229:       "-XX:CPUFeatures=ignore will disable the CPU features check; "        \

What happens when you set `CPUFeatures=ignore` on checkpoint?

src/hotspot/cpu/x86/vm_version_x86.cpp line 2569:

> 2567:       tty->print_raw(part2, sizeof(part2) - 1);
> 2568:       tty->cr();
> 2569:       vm_exit_during_initialization();

Will this work when you set `CPUFeatures=generic` before checkpoint and don't set anything during restore? The option will keep its value and this might trigger the error.
If you don't want to add some extra tests you might piggyback in `VMOptionsTest`.

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PR Review Comment: https://git.openjdk.org/crac/pull/100#discussion_r1288688744
PR Review Comment: https://git.openjdk.org/crac/pull/100#discussion_r1288686707