Bezüglich Anish's Nachricht vom 08.06.2017 14:35 (localtime):
> Hi Harry,
>>I thought I'd save these expensive VM_Exits by using the passthru path.
> Completely wrong, is it?
> It depends on which processor you are using. For example APICv was
> introduced in IvyBridge which enabled h/w assisted localAPIC rather than
> using s/w emulated, bhyve supports it on Intel processors.
> Intel Broadwell introduced PostedInterrupt which enabled interrupt to
> delivered to guest directly, bypassing hypervisor for
> passthrough devices. Emulated devices interrupt will still go through
That's very interesting, thanks so much!
I wasn't ware that there were post VT-c improvements, guess I'll have to
refresh my very basic knowledge urgently.
I'm still usign IvyBridge (E3v2) with this "new" machine, but haven't
ever heard/thought about APCIv!
> You can verify capability using sysctl hw.vmm.vmx. What processor you
> are using for these performance benchmarking?
I did very simply 'time cp' with 8GB files over NFSv4, which come from
ZFS-cache on the remote side and locally watching host+guest vmstat.
> Can you run a simple experiment, assign pptdev interrupts to core that's
> not running guest/vcpu? This will reduce #VMEXIT on vcpu which we know
> is expensive.
Interesting approach. But I have no idea how I should assign a PCIe
specific core to a PCIe dev. Is it pptdev specific? The tunables in
device.hints(5) can't be used for that, can they?
It seems pptdev(0) couldn't get a man page yet, but I'll have a look at
the sources, maybe I can find hints until earth has done it's job and
present you the same nice sunshine I'm enjoying today :-)
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