On Mon, 2018-01-08 at 18:07 +0100, Yves-Alexis Perez wrote: > On Sun, 2018-01-07 at 11:18 +0100, Willy Tarreau wrote: > > - the highest performance impact on VMs comes from having PTI on the > > guest kernel (-45%). At this point it makes no difference whether > > the host kernel has it or not. > > Hi Willy, > > out of curiosity, is the pcid/invpcid flags exposed to and used by your guest > CPU? It might very well that the PCID optimisations are not used by the guests > here, and it might be worth either checking on bare metal or with the PCID > optimisations enabled.
More details on this: https://groups.google.com/forum/m/#!topic/mechanical-sympathy/L9mHTbeQLNU Regards, -- Yves-Alexis
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