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Although I'm running KVM/qemu with the <cpu mode='host-passthrough'/> option, the guest machine has only 4096 KB of cpu cache, while the host cpu has 8192 KB (i just verified the output of /proc/cpuinfo)

Does that affect performance? What's the reason for this difference?

Thanks in advance.

user1320304
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1 Answers1

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Depending on the type of host CPU... this is very easy to explain. Intel's "Dual Core" processors actually count as two CPUs, yes... but they do not share their cache. You actually get 4mb of cache per core.

As far as performance goes, I doubt you'll see much of a gain/loss from the extra cache... unless you're doing some heavy CPU intensive tasks that are multi-threaded. Even in this case, you'd see a better performance improvement if you just added the 2nd core to the guest machine.

TheCompWiz
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