This will allow userspace to reason with the total number of CPUs, not just the current number of online CPUs. -- Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer T: +44 (0)1223 225 900, http://www.citrix.com _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
On 03/13/2012 12:52 PM, Andrew Cooper wrote:> This will allow userspace to reason with the total number of CPUs, not > just the current number of online CPUs. > > -- Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer T: +44 (0)1223 225 > 900, http://www.citrix.com > > xl-info-max_cpu_id.patch > > > # HG changeset patch > # Parent 5d20d2f6ffed0a49f030f04a8870f1926babbcbf > xl: display max_cpu_ids for xl info > > Expose "max_cpu_id" in stdout from `xl info` > > Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> > > diff -r 5d20d2f6ffed tools/libxl/xl_cmdimpl.c > --- a/tools/libxl/xl_cmdimpl.c > +++ b/tools/libxl/xl_cmdimpl.c > @@ -3734,6 +3734,7 @@ static void output_physinfo(void) > } > > printf("nr_cpus : %d\n", info.nr_cpus); > + printf("max_cpu_id : %d\n", info.max_cpu_id);Is this true: nr_cpus = max_cpu_id + 1 ? Zhigang> printf("nr_nodes : %d\n", info.nr_nodes); > printf("cores_per_socket : %d\n", info.cores_per_socket); > printf("threads_per_core : %d\n", info.threads_per_core); > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel_______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
On 13/03/12 19:15, Zhigang Wang wrote:> On 03/13/2012 12:52 PM, Andrew Cooper wrote: >> This will allow userspace to reason with the total number of CPUs, not >> just the current number of online CPUs. >> >> -- Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer T: +44 >> (0)1223 225 900, http://www.citrix.com >> >> xl-info-max_cpu_id.patch >> >> >> # HG changeset patch >> # Parent 5d20d2f6ffed0a49f030f04a8870f1926babbcbf >> xl: display max_cpu_ids for xl info >> >> Expose "max_cpu_id" in stdout from `xl info` >> >> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> >> >> diff -r 5d20d2f6ffed tools/libxl/xl_cmdimpl.c >> --- a/tools/libxl/xl_cmdimpl.c >> +++ b/tools/libxl/xl_cmdimpl.c >> @@ -3734,6 +3734,7 @@ static void output_physinfo(void) >> } >> >> printf("nr_cpus : %d\n", info.nr_cpus); >> + printf("max_cpu_id : %d\n", info.max_cpu_id); > > Is this true: nr_cpus = max_cpu_id + 1 ? > > Zhigangif and only if all cpus are online. nr_cpus is set to nr_online_cpus() in the hypercall, while max_cpu_id is set to nr_cpu_ids-1. nr_cpus is liable to change during runtime, while max_cpu_id is not. ~Andrew> >> printf("nr_nodes : %d\n", info.nr_nodes); >> printf("cores_per_socket : %d\n", info.cores_per_socket); >> printf("threads_per_core : %d\n", info.threads_per_core); >> >> >> _______________________________________________ >> Xen-devel mailing list >> Xen-devel@lists.xen.org >> http://lists.xen.org/xen-devel >-- Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer T: +44 (0)1223 225 900, http://www.citrix.com _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Andrew Cooper writes ("[Xen-devel] xl: expose max_cpu_id from `xl
info`"):> xl: display max_cpu_ids for xl info
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
On 03/14/2012 06:45 AM, Andrew Cooper wrote:> On 13/03/12 19:15, Zhigang Wang wrote: >> On 03/13/2012 12:52 PM, Andrew Cooper wrote: >>> This will allow userspace to reason with the total number of CPUs, not >>> just the current number of online CPUs. >>> >>> -- Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer T: +44 (0)1223 225 >>> 900, http://www.citrix.com >>> >>> xl-info-max_cpu_id.patch >>> >>> >>> # HG changeset patch >>> # Parent 5d20d2f6ffed0a49f030f04a8870f1926babbcbf >>> xl: display max_cpu_ids for xl info >>> >>> Expose "max_cpu_id" in stdout from `xl info` >>> >>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> >>> >>> diff -r 5d20d2f6ffed tools/libxl/xl_cmdimpl.c >>> --- a/tools/libxl/xl_cmdimpl.c >>> +++ b/tools/libxl/xl_cmdimpl.c >>> @@ -3734,6 +3734,7 @@ static void output_physinfo(void) >>> } >>> >>> printf("nr_cpus : %d\n", info.nr_cpus); >>> + printf("max_cpu_id : %d\n", info.max_cpu_id); >> >> Is this true: nr_cpus = max_cpu_id + 1 ? >> >> Zhigang > > if and only if all cpus are online. > > nr_cpus is set to nr_online_cpus() in the hypercall, while max_cpu_id is set > to nr_cpu_ids-1. > > nr_cpus is liable to change during runtime, while max_cpu_id is not. > > ~AndrewIf this is the case, I think nr_cpus is a bit confusing. Can we make it always representing the number of physical cpus (from hypervisor''s viewpoint, not dom0)? Zhigang> >> >>> printf("nr_nodes : %d\n", info.nr_nodes); >>> printf("cores_per_socket : %d\n", info.cores_per_socket); >>> printf("threads_per_core : %d\n", info.threads_per_core); >>> >>> >>> _______________________________________________ >>> Xen-devel mailing list >>> Xen-devel@lists.xen.org >>> http://lists.xen.org/xen-devel >> > > -- > Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer > T: +44 (0)1223 225 900, http://www.citrix.com_______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
<snip>>>> Is this true: nr_cpus = max_cpu_id + 1 ? >>> >>> Zhigang >> >> if and only if all cpus are online. >> >> nr_cpus is set to nr_online_cpus() in the hypercall, while max_cpu_id >> is set to nr_cpu_ids-1. >> >> nr_cpus is liable to change during runtime, while max_cpu_id is not. >> >> ~Andrew > > If this is the case, I think nr_cpus is a bit confusing. Can we make > it always representing the number of physical cpus (from hypervisor''s > viewpoint, not dom0)? > > Zhigang > >No. The names here reflect the hypercall name parameters. The hypercall cant be changed because it is an ABI, and the "name : value" pairs here cant be changed because of backward compatibility with the previous toolstack. -- Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer T: +44 (0)1223 225 900, http://www.citrix.com
On 03/14/2012 12:24 PM, Andrew Cooper wrote:> <snip> >>>> Is this true: nr_cpus = max_cpu_id + 1 ? >>>> >>>> Zhigang >>> if and only if all cpus are online. >>> >>> nr_cpus is set to nr_online_cpus() in the hypercall, while max_cpu_id >>> is set to nr_cpu_ids-1. >>> >>> nr_cpus is liable to change during runtime, while max_cpu_id is not. >>> >>> ~Andrew >> If this is the case, I think nr_cpus is a bit confusing. Can we make >> it always representing the number of physical cpus (from hypervisor''s >> viewpoint, not dom0)? >> >> Zhigang >> >> > No. The names here reflect the hypercall name parameters. The > hypercall cant be changed because it is an ABI, and the "name : value" > pairs here cant be changed because of backward compatibility with the > previous toolstack. >Ok. Thanks for you info. I think nr_online_cpus() is the right thing here: it represents online physical cpus from hypervisor''s viewpoint. It''s fine to add this output here if you need it. But for most of the xen users, the current nr_cpus should be what they want (for how many pcpus they can use). Other ways to get full hardware info could be BIOS/SMBIOS/DMI, and I think it''s better than xl info. Thanks, Zhigang
Reasonably Related Threads
- [PATCH] xl: remove duplicate line
- [PATCH] nr_cpus calculation problem due to incorrect sockets_per_node
- [PATCH 00 of 16] libxl: autogenerate type definitions and destructor functions
- xl list shows dom0 name as (null) in Xen 4.2.3
- 4.2.2 pci-passthrough crashes Dell Poweredge R710