pub struct SMP { /* private fields */ }Expand description
Simulate a SMP system with n CPUs initially present on
the machine type board. On boards supporting CPU hotplug, the optional
maxcpus parameter can be set to enable further CPUs to be
added at runtime. When both parameters are omitted, the maximum number
of CPUs will be calculated from the provided topology members and the
initial CPU count will match the maximum number. When only one of them
is given then the omitted one will be set to its counterpart’s value.
Both parameters may be specified, but the maximum number of CPUs must
be equal to or greater than the initial CPU count. Product of the
CPU topology hierarchy must be equal to the maximum number of CPUs.
Both parameters are subject to an upper limit that is determined by
the specific machine type chosen.
To control reporting of CPU topology information, values of the topology parameters can be specified. Machines may only support a subset of the parameters and different machines may have different subsets supported which vary depending on capacity of the corresponding CPU targets. So for a particular machine type board, an expected topology hierarchy can be defined through the supported sub-option. Unsupported parameters can also be provided in addition to the sub-option, but their values must be set as 1 in the purpose of correct parsing.
Either the initial CPU count, or at least one of the topology parameters must be specified. The specified parameters must be greater than zero, explicit configuration like “cpus=0” is not allowed. Values for any omitted parameters will be computed from those which are given.
For example, the following sub-option defines a CPU topology hierarchy (2 sockets totally on the machine, 2 cores per socket, 2 threads per core) for a machine that only supports sockets/cores/threads. Some members of the option can be omitted but their values will be automatically computed: