On Mon, Aug 04, 2014 at 11:38:41AM +0800, Li Wei wrote: > Hi, > > On 07/22/2014 03:25 PM, Richard W.M. Jones wrote: > > > > Did anything come of this discussion, and/or is someone working on this? > > I am working on an API to query block stats in a bulk style and proposed an > API as follow: > > virDomainBlockStatsBulkFlags(virDomainPtr dom, > virTypedParameterPtr params, > int nparams, > int ndisks, > unsigned int flags) > > @dom: pointer to domain object > @params: an array of typed param to be populated with block stats > @nparams: how many params used for each block device > @ndisks: how many block devices to query > @flags: flags to filter block devices (not used for now) > > Returns -1 in case of error, 0 in case of success. > with params == NULL, nparams == -1, ndisks == 1, return number of params for > each block device. > with params == NULL, nparams == -1, ndisks == -1, return number of disks in > the domain. > > A typical usage of this API should be: > nparams = virDomainBlockStatsBulkFlags(dom, NULL, -1, 1, 0); > ndisks = virDomainBlockStatsBulkFlags(dom, NULL, -1, -1, 0); > > params = VIR_ALLOC_N(params, nparams * ndisks); > > ret = virDomainBlockStatsBulkFlags(dom, params, nparams, ndisks, 0); > > ... do something with params > > VIR_FREE(params); > > With this bulk API, virt-top can updates in a short interval for a domain > with a lot of disks. > Any comments?
I think this works OK for the case where you have 1 domains with lots of disks. However if you have a large number of domains each with 1 or 2 disks I think you would have the same problem as currently. Is it possible to design an API that can work across all domains in a single call? > PS: > It seems we need a bunch of bulk APIs to query stats, I wonder if I can > submit a patchset for each > bulk API or must supply all the bulk APIs in one patchset? Whichever is easiest to review. I suspect that smaller patches, each containing a single new API, will be simpler to review, but that's just my opinion. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/ -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
