KVM: stats: Support linear and logarithmic histogram statistics

Add new types of KVM stats, linear and logarithmic histogram. Histogram are very useful for observing the value distribution of time or size related stats.

Jing Zhang committed 5 years ago

Commit f95937c1 parent 73143038 files · +82 −43Browse files

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include/uapi/linux/kvm.h+7−4

 #define KVM_STATS_TYPE_CUMULATIVE	(0x0 << KVM_STATS_TYPE_SHIFT)
 #define KVM_STATS_TYPE_INSTANT		(0x1 << KVM_STATS_TYPE_SHIFT)
 #define KVM_STATS_TYPE_PEAK		(0x2 << KVM_STATS_TYPE_SHIFT)
-#define KVM_STATS_TYPE_MAX		KVM_STATS_TYPE_PEAK
+#define KVM_STATS_TYPE_LINEAR_HIST	(0x3 << KVM_STATS_TYPE_SHIFT)
+#define KVM_STATS_TYPE_LOG_HIST		(0x4 << KVM_STATS_TYPE_SHIFT)
+#define KVM_STATS_TYPE_MAX		KVM_STATS_TYPE_LOG_HIST
 #define KVM_STATS_UNIT_SHIFT		4
 #define KVM_STATS_UNIT_MASK		(0xF << KVM_STATS_UNIT_SHIFT)
  * @size: The number of data items for this stats.
  *        Every data item is of type __u64.
  * @offset: The offset of the stats to the start of stat structure in
- *          struture kvm or kvm_vcpu.
+ *          structure kvm or kvm_vcpu.
- * @unused: Unused field for future usage. Always 0 for now.
+ * @bucket_size: A parameter value used for histogram stats. It is only used
+ *		for linear histogram stats, specifying the size of the bucket;
  * @name: The name string for the stats. Its size is indicated by the
  *        &kvm_stats_header->name_size.
  */
 	__s16 exponent;
 	__u16 size;
 	__u32 offset;
-	__u32 unused;
+	__u32 bucket_size;
 	char name[];
 };