mirror of
https://gitlab.com/libvirt/libvirt.git
synced 2025-02-07 04:07:17 +00:00
eee7bd4ecb
Introduce initial support for domainBlockStats API call that allow us to query block device statistics. OpenStack nova uses this API call to query block statistics, alongside virDomainMemoryStats and virDomainInterfaceStats. Note that this patch only introduces it for VBD for starters. QDisk would come in a separate patch series. A new statistics data structure is introduced to fit common statistics among others specific to the underlying block backends. For the VBD statistics on linux these are exported via sysfs on the path: "/sys/bus/xen-backend/devices/vbd-<domid>-<devid>/statistics" To calculate the block devno libxlDiskPathToID is introduced. Each backend implements its own function to extract statistics, allowing support for multiple backends and different platforms. VBD stats are exposed in reqs and number of sectors from blkback, and it's up to us to convert it to sector sizes. The sector size is gathered through xenstore in the device backend entry "physical-sector-size". BlockStatsFlags variant is also implemented which has the added benefit of getting the number of flush requests. Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
LibVirt : simple API for virtualization
Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.
Daniel Veillard <veillard@redhat.com>