6:29 a.m.
On Fri, Apr 15, 2011 at 04:43:03PM +0900, KAMEZAWA Hiroyuki wrote:
On Fri, 15 Apr 2011 09:43:15 +0200
Matthias Bolte <matthias.bolte(a)googlemail.com> wrote:
> 2011/4/15 KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com>:
> > Per (host) cpu activity of VMs are very insterested numbers
> > when running VMs on large SMPs. virt-top -1 mode tries to
> > provide the information. (But it's not implemented.)
> >
> > This patch adds a libvirt interface to get per cpu statistics
> > of each nodes. This patch just adds an interface and driver
> > entry points. So,
> > - doesn't include patches for python.
> > - doesn't include any driver.
> >
> > Following patches will add some drivers and codes for python.
> >
> > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com>
> > ---
> > include/libvirt/libvirt.h.in | 13 ++++++++++
> > src/driver.h | 6 ++++
> > src/esx/esx_driver.c | 1 +
> > src/libvirt.c | 55
++++++++++++++++++++++++++++++++++++++++++
> > src/libvirt_public.syms | 4 +++
> > src/libxl/libxl_driver.c | 1 +
> > src/lxc/lxc_driver.c | 1 +
> > src/openvz/openvz_driver.c | 1 +
> > src/phyp/phyp_driver.c | 1 +
> > src/qemu/qemu_driver.c | 1 +
> > src/remote/remote_driver.c | 1 +
> > src/test/test_driver.c | 1 +
> > src/uml/uml_driver.c | 1 +
> > src/vbox/vbox_tmpl.c | 1 +
> > src/vmware/vmware_driver.c | 1 +
> > src/xen/xen_driver.c | 1 +
> > src/xenapi/xenapi_driver.c | 1 +
> > 17 files changed, 91 insertions(+), 0 deletions(-)
> >
> > diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
> > index 5783303..6b9292c 100644
> > --- a/include/libvirt/libvirt.h.in
> > +++ b/include/libvirt/libvirt.h.in
> > @@ -400,6 +400,13 @@ struct _virDomainMemoryStat {
> >
> > typedef virDomainMemoryStatStruct *virDomainMemoryStatPtr;
> >
> > +typedef struct _virDomainPcpuStat virDomainPcpuStatStruct;
> > +
> > +struct _virDomainPcpuStat {
> > + unsigned long long cpuTime;
> > +};
> > +
>
> NACK to adding another public struct to the API.
Oh, yes. I searched a sutiable existing API but cannot found.
Maybe adding new enum to Usui's work will be good but I need an array.
Hmm, returning an array of unsigned long long is ok ?
> It's not expendable.
> As a stylistic nit pleas don't use the term PCPU as this looks like
> "Physical CPU". Just call it virDomainPerVcpuStat at least.
>
Ah, no, this is PerPhysicalStat
> Also do you really need the absolute CPU time?
yes, for virt-top -1.
I don't think that is correct. What virt-top ultimately displays
to the end user is a % utilization. So it would be happy to get
data in either % util & display that directly, or get absolute
CPU time and calculate deltas to display % util.
I wonder if we could provide an API that could be used to provide
either per-VCPU or per-PCPU statistics in one go, so that we
can finally have an API for cpu time that works well for VMWare.
eg
typedef struct _virDomainCPUTime virDomainCPUTime;
typedef virDomainCPUTime *virDomainCPUTimePtr;
#define VIR_DOMAIN_CPUTIME_ABS "abs"
#define VIR_DOMAIN_CPUTIME_UTIL "util"
...define more stats later if desired...
struct _virDomainCPUTime {
char field[VIR_DOMAIN_CPU_TIME_FIELD_LENGTH];
unsigned long long value;
};
typedef enum {
VIR_DOMAIN_CPU_TIME_VIRTUAL = 0,
VIR_DOMAIN_CPU_TIME_PHYSICAL = 1,
} virDomainCPUTimeFlags;
int virDomainGetCPUTime(virDomainPtr dom,
virDomainCPUTimePtr stats,
int *nstats,
unsigned int flags);
When querying per-virtual CPU time, nstats would be the number of
virtual CPUs in the guest. eg
virDomainInfo info;
virDomainGetInfo(dom, &info);
virDomainCPUTimePtr stats;
stats = malloc(sizeof(*stats)*info.nrVirtCPU);
virDomainGetCPUTime(dom, stats, info.nrVirtCPU,
VIR_DOMAIN_CPU_TIME_VIRTUAL);
Or to get the break down per physical CPU, use the VIR_NODEINFO_MAX_CPUS
macro
virNodeInfo info;
virNodeGetInfo(conn, &info);
virDomainCPUTimePtr stats;
stats = malloc(sizeof(*stats)*VIR_NODEINFO_MAX_CPUS(info))
virDomainGetCPUTime(dom, stats, VIR_NODEINFO_MAX_CPUS(info),
VIR_DOMAIN_CPU_TIME_PHYSICAL);
We could also allow 'nstats' to be 0, in which case the API
would simply populate 'nstats' with the required number and
return. The caller can then re-invoke with correct nstats
and allocated memory.
Daniel
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