I would expect xc_domain_getinfolist() to just be an extended version
of xc_domain_getinfo() but filling-up a range of xc_dominfo_t. However
the declaration in xenctrl.h is
int xc_domain_getinfolist(int xc_handle,
uint32_t first_domain,
unsigned int max_domains,
xc_domaininfo_t *info);
i.e. a different info pointer type than
int xc_domain_getinfo(int xc_handle,
uint32_t first_domid,
unsigned int max_doms,
xc_dominfo_t *info);
is that a typo ? xc_domaininfo_t is defined as dom0_getdomaininfo_t
which is a distinct type from xc_dominfo_t, with slightly different
characteristics. Any reason for that disparity in the type returned
between those two functions ?
Daniel
--
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Daniel Veillard wrote:> I would expect xc_domain_getinfolist() to just be an extended version >of xc_domain_getinfo() but filling-up a range of xc_dominfo_t. However >the declaration in xenctrl.h is > > int xc_domain_getinfolist(int xc_handle, > uint32_t first_domain, > unsigned int max_domains, > xc_domaininfo_t *info); > >i.e. a different info pointer type than > > int xc_domain_getinfo(int xc_handle, > uint32_t first_domid, > unsigned int max_doms, > xc_dominfo_t *info); > >is that a typo ? xc_domaininfo_t is defined as dom0_getdomaininfo_t >which is a distinct type from xc_dominfo_t, with slightly different >characteristics. Any reason for that disparity in the type returned >between those two functions ? > >xc_domain_getinfolist is a batched interface to xc_domain_getinfo from the hypervisor perspective. That is, getinfolist will only make a single hypercall whereas getinfo will make up to max_doms hypercalls. getinfo massages the returned data into a more python friendly structure (xc_dominfo_t) whereas getinfolist returns the raw results from the hypercall (which is just typedef''d to xc_domaininfo_t. The argument for getinfolist was performance. Applications that require as low-overhead as possible polling info polling mechanism can use getinfolist. Regards, Anthony Liguori>Daniel > > >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On Mon, Oct 24, 2005 at 02:27:52PM -0500, Anthony Liguori wrote:> Daniel Veillard wrote: > > >I would expect xc_domain_getinfolist() to just be an extended version > >of xc_domain_getinfo() but filling-up a range of xc_dominfo_t. However > >the declaration in xenctrl.h is > > > > int xc_domain_getinfolist(int xc_handle, > > uint32_t first_domain, > > unsigned int max_domains, > > xc_domaininfo_t *info); > > > >i.e. a different info pointer type than > > > > int xc_domain_getinfo(int xc_handle, > > uint32_t first_domid, > > unsigned int max_doms, > > xc_dominfo_t *info); > > > >is that a typo ? xc_domaininfo_t is defined as dom0_getdomaininfo_t > >which is a distinct type from xc_dominfo_t, with slightly different > >characteristics. Any reason for that disparity in the type returned > >between those two functions ? > > > > > xc_domain_getinfolist is a batched interface to xc_domain_getinfo from > the hypervisor perspective. That is, getinfolist will only make a > single hypercall whereas getinfo will make up to max_doms hypercalls. > > getinfo massages the returned data into a more python friendly structure > (xc_dominfo_t) whereas getinfolist returns the raw results from the > hypercall (which is just typedef''d to xc_domaininfo_t. > > The argument for getinfolist was performance. Applications that require > as low-overhead as possible polling info polling mechanism can use > getinfolist.Okay, thanks ! Daniel -- Daniel Veillard | Red Hat http://redhat.com/ veillard@redhat.com | libxml GNOME XML XSLT toolkit http://xmlsoft.org/ http://veillard.com/ | Rpmfind RPM search engine http://rpmfind.net/ _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel