Ian Pratt
2006-May-09 15:05 UTC
RE: [Xen-devel] Setting dom0-cpus to 0 doesn''t use all cpus asdocumented
> The comments for dom0-cpus in the xend-config.sxp file > indicate that setting this value to 0 in an SMP system will > cause dom0 to use all the available CPUs. However, it appears > as if setting this value to 0 does not change the number of > CPUs at all. > > I''m running SLES10 Beta 11 and xen-unstable changeset 9960 on > a Unisys ES7000 with 32 CPUs and 32GB memory. In > xend-config.sxp, dom0-cpus is set to 0. When xen dom0 boots, > it is using all 32 procs (as reported by ''grep processor > /proc/cpuinfo | wc -l''). > > If I edit the xend-config.sxp file, change the value of > dom0-cpus to 1, and restart xend, dom0 correctly uses 1 CPUs. > If I then change dom0-cpus to 0 and restart xend, dom0 still > uses 1 cpu. The only way to have dom0 use 32 cpus again is to > either set the value of dom0-cpus to 32, or reboot xen. > > Has anyone else seen this behavior?You can just use the normal xm commands to vary the number of CPUs. Restarting xend is a rather brutal way of trying to achieve the same thing... Ian _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Ryan Harper
2006-May-09 15:44 UTC
Re: [Xen-devel] Setting dom0-cpus to 0 doesn''t use all cpus asdocumented
* Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk> [2006-05-09 10:07]:> > The comments for dom0-cpus in the xend-config.sxp file > > indicate that setting this value to 0 in an SMP system will > > cause dom0 to use all the available CPUs. However, it appears > > as if setting this value to 0 does not change the number of > > CPUs at all. > > > > I''m running SLES10 Beta 11 and xen-unstable changeset 9960 on > > a Unisys ES7000 with 32 CPUs and 32GB memory. In > > xend-config.sxp, dom0-cpus is set to 0. When xen dom0 boots, > > it is using all 32 procs (as reported by ''grep processor > > /proc/cpuinfo | wc -l''). > > > > If I edit the xend-config.sxp file, change the value of > > dom0-cpus to 1, and restart xend, dom0 correctly uses 1 CPUs. > > If I then change dom0-cpus to 0 and restart xend, dom0 still > > uses 1 cpu. The only way to have dom0 use 32 cpus again is to > > either set the value of dom0-cpus to 32, or reboot xen. > > > > Has anyone else seen this behavior? > > You can just use the normal xm commands to vary the number of CPUs. > Restarting xend is a rather brutal way of trying to achieve the same > thing...Is it worth keeping dom0-cpus then? -- Ryan Harper Software Engineer; Linux Technology Center IBM Corp., Austin, Tx (512) 838-9253 T/L: 678-9253 ryanh@us.ibm.com _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel