On Tue, Aug 16, 2016 at 11:07:41AM +0800, Dou Liyang wrote: > This document describes how to use cpu hotplug in QEMU. > > Signed-off-by: Andrew Jones <drjo...@redhat.com> > Signed-off-by: Dou Liyang <douly.f...@cn.fujitsu.com> > --- > Change log v3 -> v4 > From David's advice > 1. add spapr examples > 2. Fix some comment > From drew's advice > 1. Fix some syntax > > Change log v2 -> v3: > From drew's advice: > 1. modify the examples. > 2. Fix some syntax. > > Change log v1 -> v2: > From Fam's advice: > 1. Fix some comment. > > Change log v1: > From Igor's advice: > 1. Remove any mentioning of apic-id from the document. > 2. Remove the "device_del qom_path" from the CPU hot-unplug. > 3. Fix some comment. > > docs/cpu-hotplug.txt | 132 > +++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 132 insertions(+) > create mode 100644 docs/cpu-hotplug.txt > > diff --git a/docs/cpu-hotplug.txt b/docs/cpu-hotplug.txt > new file mode 100644 > index 0000000..0c1bfe9 > --- /dev/null > +++ b/docs/cpu-hotplug.txt > @@ -0,0 +1,132 @@ > +QEMU CPU hotplug > +================ > + > +This document explains how to use the CPU hotplug feature in QEMU, > +which regards the CPU as a device, using -device/device_add and > +device_del. > + > +QEMU support was merged for 2.7. > + > +Guest support is required for CPU hotplug to work. > + > +CPU hot-plug > +------------ > + > +In order to be able to hotplug CPUs, QEMU has to be told the maximum > +number of CPUs which the guest can have. This is done at startup time > +by means of the -smp command-line option, which has the following > +format: > + > + -smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads] > + [,sockets=sockets] > + > +Where, > + > + - "cpus" sets the number of CPUs to 'n' [default=1]. > + - "maxcpus" sets the maximum number of CPUs, including offline VCPUs > + for hotplug. > + - "sockets" sets the number of discrete sockets in the system. > + - "cores" sets the number of CPU cores on one socket. > + - "threads" sets the number of threads on one CPU core. > + > +For example, the following command-line: > + > + qemu [...] -smp 3,maxcpus=8,sockets=2,cores=2,threads=2
This is not a valid topology on sPAPR. In the documentation, why not have a bit more generic topology that is likely to work for most archs ? Like -smp 4,maxcpus=8,sockets=2,cores=2,threads=2. Regards, Bharata.
