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Patches Provide For Much Faster In-Kernel Zstd Due To Embarrassingly Bad Inefficiency (www.phoronix.com)
submitted 2 months ago by to c/linux@programming.dev
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[–] 14 points 2 months ago

Usama Arif found that with the three patches to just probe BMI2 CPU support only once, it yield a 71% reduction in decompression time and a 18% reduction in compression time for a crypto_acomp benchmark.

Wow

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    [–] 4 points 2 months ago (1 child)

    Is it that slow outside of a VM? Either way, this seems like a very sensible patch.

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  • [–] 4 points 2 months ago* (last edited 2 months ago)

    It's only slightly faster. cpuid is a serialising instruction, which means all the instructions before it have to complete, removing any gains from pipelining and out of order execution. However for a VM this also triggers a VM exit, where the hypervisor takes over to modify the values for the guest.

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