In addition to the number of virtual cores, you can configure how much resources
a VM can get in relation to the host CPU time and also in relation to other
VMs.
-With the *cpulimit* (`Host CPU Time') option you can limit how much CPU time the
-whole VM can use on the host. It is a floating point value representing CPU
+With the *cpulimit* (``Host CPU Time'') option you can limit how much CPU time
+the whole VM can use on the host. It is a floating point value representing CPU
time in percent, so `1.0` is equal to `100%`, `2.5` to `250%` and so on. If a
single process would fully use one single core it would have `100%` CPU Time
usage. If a VM with four cores utilizes all its cores fully it would
footnote:[Meltdown Attack https://meltdownattack.com/] mitigation approach. In
Linux the mitigation is called 'Kernel Page-Table Isolation (KPTI)', which
effectively hides the Kernel memory from the user space, which, without PCID,
-is a expensive operation footnote:[PCID is now a critical performance/security
+is an expensive operation footnote:[PCID is now a critical performance/security
feature on x86
https://groups.google.com/forum/m/#!topic/mechanical-sympathy/L9mHTbeQLNU].
* The guest Operating System must be updated to a version which mitigates the
attack and utilizes the PCID feature marked by its flag.
-To check if the {pve} host support PCID, execute the following command as root:
+To check if the {pve} host supports PCID, execute the following command as root:
----
# grep ' pcid ' /proc/cpuinfo
----
-If this does not return empty your hosts CPU has support for PCID. If you use
-`host' as CPU type and the guest OS is able to use it, your done.
-Else, the PCID CPU flag needs to get set for the virtual CPU. This can be done,
-for example, by editing the CPU through the WebUI.
+If this does not return empty your host's CPU has support for PCID. If you use
+`host' as CPU type and the guest OS is able to use it, you're done.
+Otherwise you need to set the PCID CPU flag for the virtual CPU. This can be
+done by editing the CPU options through the WebUI.
NUMA
^^^^