Re: [libvirt] [RFC][scale] new API for querying domains stats
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?
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?
Thanks,
Li Wei
Rich.