I recognized (with npt disabled) the VM is getting slower over time,
like in Windows the system process is taking more and more CPU usage. A
soft restart does help makeing it "usable" again. Also wondering if this
is an hardware related issue in Ryzen, so the upcoming Naples does have
it too? This would be a nogo for the server platform and, in my eyes,
the death even pre-released.
Regards
Am 03.05.2017 um 18:28 schrieb Nick Sarnie:
On Wed, May 3, 2017 at 10:37 AM, Matthias Ehrenfeuchter <[email protected]> wrote:
Hi,
There are a lot of messages/threads out there about bad performance while
using AMDs Ryzen with KVM GPU passthrough. It revolves all on
enabling/disabling npt, while enabled overall VM performance is nice but the
GPU performance gives me about 20% (and a lot of drops to zero GPU usage,
while CPU/Disk/Ram also doing nothing) compared to npt disabled. But while
npt is disabled overall VM performance is like beeing on 4x86 with floppy
disk as only storage. (Ex. it takes 2 seconds just to open startmenu while
host and vm are in idle, and neither CPU pinning, changing CPU model,
changing storage device nor using hugepages changed anything).
So everything I read pointed to a bug in the npt implementation? Anything I
could do to get closer to the "thing" issuing this?
Best Regards
efeu
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I heard from Joerg that it might be related to a lower intercept rate
being used when NPT is enabled, but we haven't been able to find a way
to trace that to confirm.
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