Re: [libvirt] [PATCH 1/6] virNodeGetCpuTime: Expose new API

On 03/31/2011 07:55 PM, Minoru Usui wrote: > virNodeGetCpuTime: Expose new API > > include/libvirt/libvirt.h.in | 26 ++++++++++++++++++++++++++ > src/libvirt_public.syms | 1 + > 2 files changed, 27 insertions(+), 0 deletions(-) > > +/** > + * virNodeCpuTime: > + * > + * a virNodeCpuTime is a structure filled by virNodeGetCpuTime() and providing > + * the information for the cpu time of Node. > + */ > + > +typedef struct _virNodeCpuTime virNodeCpuTime; > + > +struct _virNodeCpuTime { > + unsigned long long user; > + unsigned long long system; > + unsigned long long idle; > + unsigned long long iowait; > +}; Can we portably get all of this information on Windows? If not, how do you express which values we don't know how to obtain? > @@ -593,6 +616,9 @@ int virNodeGetInfo (virConnectPtr conn, > virNodeInfoPtr info); > char * virConnectGetCapabilities (virConnectPtr conn); > > +int virNodeGetCpuTime (virConnectPtr conn, > + virNodeCpuTimePtr cpu_time); > + Rather than locking ourselves into yet another inflexible API (no flags parameter and a hard-coded struct means no way to extend this if we ever come up with some new stat to query), should we instead be following the lead of getMemoryParameters which takes a typed-name/value array to pass an arbitrary number of parameters, which allows extension without a new API?

> +++ b/src/libvirt_public.syms > @@ -434,6 +434,7 @@ LIBVIRT_0.9.0 { > virEventRunDefaultImpl; > virStorageVolDownload; > virStorageVolUpload; > + virNodeGetCpuTime; > } LIBVIRT_0.8.8; While I think that something along the lines of this API is appropriate for libvirt (indeed, knowing a host's CPU utilization can indeed be a factor for upper-level management software in deciding whether to migrate another domain on or off of the machine), it's too late to put it into 0.9.0. We'd be setting bad precedent by accepting this after the first release candidate did a feature freeze, so you'd need to adjust this to 0.9.1.

-- Eric Blake eblake(a)redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org