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-rw-r--r--qemu-options.hx29
1 files changed, 21 insertions, 8 deletions
diff --git a/qemu-options.hx b/qemu-options.hx
index 14ff35dd4e..214c477dcc 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -207,14 +207,27 @@ DEF("smp", HAS_ARG, QEMU_OPTION_smp,
QEMU_ARCH_ALL)
SRST
``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,cores=cores][,threads=threads]``
- Simulate an SMP system with n CPUs. On the PC target, up to 255 CPUs
- are supported. On Sparc32 target, Linux limits the number of usable
- CPUs to 4. For the PC target, the number of cores per die, the
- number of threads per cores, the number of dies per packages and the
- total number of sockets can be specified. Missing values will be
- computed. If any on the three values is given, the total number of
- CPUs n can be omitted. maxcpus specifies the maximum number of
- hotpluggable CPUs.
+ 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. If omitted the maximum number of CPUs will be
+ set to match the initial CPU count. Both parameters are subject to
+ an upper limit that is determined by the specific machine type chosen.
+
+ To control reporting of CPU topology information, the number of sockets,
+ dies per socket, cores per die, and threads per core can be specified.
+ The sum `` sockets * cores * dies * threads `` must be equal to the
+ maximum CPU count. CPU targets may only support a subset of the topology
+ parameters. Where a CPU target does not support use of a particular
+ topology parameter, its value should be assumed to be 1 for the purpose
+ of computing the CPU maximum count.
+
+ Either the initial CPU count, or at least one of the topology parameters
+ must be specified. Values for any omitted parameters will be computed
+ from those which are given. Historically preference was given to the
+ coarsest topology parameters when computing missing values (ie sockets
+ preferred over cores, which were preferred over threads), however, this
+ behaviour is considered liable to change.
ERST
DEF("numa", HAS_ARG, QEMU_OPTION_numa,