On Wed, Sep 02, 2020 at 04:58:39PM +0200, Stefan Sperling wrote:
> I would like to suggest an example for the EXAMPLES section which
> illustrates how a suitable stride factor can be determined (divide the
> number of desired "unused" cpus by the number of desired "used" cpus):
We can do with an example, but to me yours does not read obvious enough.
Also, `vcpu' denotes *virtual* CPUs inside domains, not CPUs on the
machine, so "CPU" (without "V") reads off in your example and conflicts
with the otherwise consistent mentions of "virtual CPUs" in this manual.
Here's my last diff incl. an example which reads a tad clearer to me and
is placed in the EXAMPLES section instead.
Feedback? OK?
Index: ldom.conf.5
===================================================================
RCS file: /cvs/src/usr.sbin/ldomctl/ldom.conf.5,v
retrieving revision 1.13
diff -u -p -r1.13 ldom.conf.5
--- ldom.conf.5 21 Feb 2020 19:39:28 -0000 1.13
+++ ldom.conf.5 14 Sep 2020 17:51:39 -0000
@@ -38,8 +38,13 @@ If no configuration for the primary doma
all CPU and memory resources not used by any guest domains.
.It Ic vcpu Ar number Ns Op : Ns Ar stride
Declare the number of virtual CPUs assigned to a domain.
-Optionally a stride can be specified to allocate additional virtual CPUs
-but not assign them to a domain.
+Optionally a stride factor can be specified to allocate
+.Ar number
+virtual CPUs
+.Ar stride
+times but not assign more than
+.Ar number
+virtual CPUs to a domain, leaving the rest unassigned.
This can be used to distribute virtual CPUs over the available CPU cores.
.It Ic memory Ar bytes
Declare the amount of memory assigned to a domain, in bytes.
@@ -112,6 +117,20 @@ domain "salmah" {
.Pp
On a machine with 32 cores and 64GB physical memory, this leaves 12 cores and
58GB memory to the primary domain.
+.Pp
+Use
+.Ar stride
+factors to distribute virtual CPUs:
+.Bd -literal -offset indent
+domain "sun" {
+ vcpu 2:4
+ memory 4G
+ vdisk "/home/sun/vdisk0"
+}
+.Ed
+On a machine with eight threads per physical core, this allocates four strides
+of two virtual CPUs to the guest domain but only assigns one stride to it, i.e.
+make it occupy an entire physical core while running on only two threads.
.Sh SEE ALSO
.Xr eeprom 8 ,
.Xr ldomctl 8 ,
