Messages in this thread | | | Date | Thu, 14 Oct 2021 10:28:00 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v1] x86/fpu: Remove opmask state from avx512_timestamp check |
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On Wed, Oct 13, 2021 at 05:36:14PM -0500, Noah Goldstein wrote: > Ping2
Why?
The original patch which added this abomination:
2f7726f95557 ("x86/fpu: Track AVX-512 usage of tasks")
says already:
the tracking mechanism is imprecise and can theoretically miss AVX-512 usage during context switch. But it has been measured to be precise enough to be useful under real-world workloads like tensorflow and linpack.
If higher precision is required, suggest user space tools to use the PMU-based mechanisms in combination.
and as you've noticed, the high 16 regs would cause a false positive too.
So what is the actual real-life use case for this?
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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