11:58 p.m.
On Fri, Apr 08, 2011 at 08:33:12PM +0900, Minoru Usui wrote:
virNodeGetCPUTime: Expose new API
Signed-off-by: Minoru Usui <usui(a)mxm.nes.nec.co.jp>
---
include/libvirt/libvirt.h.in | 64 ++++++++++++++++++++++++++++++++++++++++++
src/libvirt_public.syms | 5 +++
2 files changed, 69 insertions(+), 0 deletions(-)
diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
index bd36015..154c138 100644
--- a/include/libvirt/libvirt.h.in
+++ b/include/libvirt/libvirt.h.in
@@ -228,6 +228,57 @@ struct _virNodeInfo {
unsigned int threads;/* number of threads per core */
};
+/**
+ * virNodeCpuTime:
+ *
+ * a virNodeCpuTime is a structure filled by virNodeGetCpuTime() and providing
+ * the information for the cpu time of the node.
+ */
+
+/**
+ * Cpu Time Statistics Tags:
+ */
+typedef enum {
+ /*
+ * The cumulative CPU time which spends by kernel,
+ * when the node booting up.(in nanoseconds).
+ */
+ VIR_NODE_CPU_TIME_KERNEL = 0,
+ /*
+ * The cumulative CPU time which spends by user processes,
+ * when the node booting up.(in nanoseconds).
+ */
+ VIR_NODE_CPU_TIME_USER = 1,
+ /*
+ * The cumulative idle CPU time,
+ * when the node booting up.(in nanoseconds).
+ */
+ VIR_NODE_CPU_TIME_IDLE = 2,
+ /*
+ * The cumulative I/O wait CPU time,
+ * when the node booting up.(in nanoseconds).
+ */
+ VIR_NODE_CPU_TIME_IOWAIT = 3,
+ /*
+ * The CPU utilization.
+ * The usage value is in percent and 100% represents all CPUs on
+ * the server.
+ */
+ VIR_NODE_CPU_TIME_UTILIZATION = 4,
+
+ /*
+ * The number of statistics supported by this version of the interface.
+ * To add new statistics, add them to the enum and increase this value.
+ */
+ VIR_NODE_CPU_TIME_NR = 5,
+} virNodeCpuTimeTags;
+
+typedef struct _virNodeCpuTime virNodeCpuTime;
+
+struct _virNodeCpuTime {
+ virNodeCpuTimeTags tag;
+ unsigned long long val;
+};
NACK, the size of an enum is not defined by the C language and
hence is compiler dependant. We cannot use it as a component of a
structure in the API.
/**
* virDomainSchedParameterType:
@@ -460,6 +511,14 @@ int virDomainMigrateSetMaxSpeed(virDomainPtr domain,
typedef virNodeInfo *virNodeInfoPtr;
/**
+ * virNodeCpuTimePtr:
+ *
+ * a virNodeCpuTimePtr is a pointer to a virNodeCpuTime structure.
+ */
+
+typedef virNodeCpuTime *virNodeCpuTimePtr;
+
+/**
* virConnectFlags
*
* Flags when opening a connection to a hypervisor
@@ -593,6 +652,11 @@ int virNodeGetInfo (virConnectPtr
conn,
virNodeInfoPtr info);
char * virConnectGetCapabilities (virConnectPtr conn);
+int virNodeGetCpuTime (virConnectPtr conn,
+ virNodeCpuTimePtr stats,
+ unsigned int nr_stats,
+ unsigned int flags);
+
I don't understand how the API is suppoed to work. Suppose you want
the cumulative CPU time, how do you ask for it ? Seems you can't ! You
just ask for a big stucture hoping that on return you may find it within
the results. That looks broken to me.
Either you make a simple API giving back an unsigned long long and
you use the virNodeCpuTimeTags as the flag value
int virNodeGetCpuTime(virConnectPtr conn, unsigned long long *time,
unsigned int flags);
and the flags indicate the value you're interested into, but in that
case you have to ask multiple times. Or you make the VIR_NODE_CPU_TIME_*
values a bit field, and you pass an array
int virNodeGetCpuTime(virConnectPtr conn,
unsigned long long *stats,
unsigned int nr_stats,
unsigned int flags);
where flags is the logical or of the values you are interested into, and
the implementation put them in order based on the VIR_NODE_CPU_TIME_*
values. But in that case you must fail if one of the statistics is not
available.
But an API where you "go fishing" and you don't know upfront on a
successful return if you got the data you're interested into sounds
broken to me
Daniel
--
Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
daniel(a)veillard.com | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library http://libvirt.org/