From: Peter Krempa <pkrempa@redhat.com>
Add documentation and constants for constructing the stats field names
for latency histograms and expose them in the qemu driver:
Example:
block.1.latency_histogram.read.bin.count=9
block.1.latency_histogram.read.bin.0.start=0
block.1.latency_histogram.read.bin.0.value=0
block.1.latency_histogram.read.bin.1.start=10
block.1.latency_histogram.read.bin.1.value=0
block.1.latency_histogram.read.bin.2.start=100
block.1.latency_histogram.read.bin.2.value=0
block.1.latency_histogram.read.bin.3.start=1000
block.1.latency_histogram.read.bin.3.value=1047
block.1.latency_histogram.read.bin.4.start=10000
block.1.latency_histogram.read.bin.4.value=2131
block.1.latency_histogram.read.bin.5.start=100000
block.1.latency_histogram.read.bin.5.value=0
block.1.latency_histogram.read.bin.6.start=1000000
block.1.latency_histogram.read.bin.6.value=0
block.1.latency_histogram.read.bin.7.start=10000000
block.1.latency_histogram.read.bin.7.value=0
block.1.latency_histogram.read.bin.8.start=100000000
block.1.latency_histogram.read.bin.8.value=0
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
---
docs/manpages/virsh.rst | 7 ++
include/libvirt/libvirt-domain.h | 113 +++++++++++++++++++++++++++++++
src/qemu/qemu_driver.c | 43 ++++++++++++
3 files changed, 163 insertions(+)
diff --git a/docs/manpages/virsh.rst b/docs/manpages/virsh.rst
index a9d691824e..ff0cf1a715 100644
--- a/docs/manpages/virsh.rst
+++ b/docs/manpages/virsh.rst
@@ -2811,6 +2811,13 @@ Information listed includes:
pending write operations in the defined interval
* ``block.<num>.timed_group.<num>.zone_append_queue_depth_avg`` - average number
of pending zone append operations in the defined interval
+* ``block.<num>.latency_histogram.<type>.bin.count`` - number of bins in
+ latency histogram. <type> is one of ``read``, ``write``, ``zone_append``, or
+ ``flush``
+* ``block.<num>.latency_histogram.<type>.bin.<num>.start`` start boundary of
+ a latency histogram bin in nanoseconds of given operation duration
+* ``block.<num>.latency_histogram.<type>.bin.<num>.value`` current number of
+ events corresponding to the given bin and type
*--iothread* returns information about IOThreads on the running guest
diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
index 893359aaae..56c21dcf25 100644
--- a/include/libvirt/libvirt-domain.h
+++ b/include/libvirt/libvirt-domain.h
@@ -3896,6 +3896,119 @@ struct _virDomainStatsRecord {
*/
# define VIR_DOMAIN_STATS_BLOCK_SUFFIX_TIMED_GROUP_SUFFIX_ZONE_APPEND_QUEUE_DEPTH_AVG ".zone_append_queue_depth_avg"
+/**
+ * VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_READ_PREFIX:
+ *
+ * The parameter name prefix to access 'read' latency histograms. Concatenate
+ * the prefix with either:
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_COUNT
+ * to get the number of bins in given histogram
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_PREFIX and
+ * entry number formatted as an unsigned integer and one of the latency
+ * histogram suffix parameters to compelte a full bin parameter name
+ *
+ * Since: 12.1.0
+ */
+# define VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_READ_PREFIX ".latency_histogram.read."
+
+/**
+ * VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_WRITE_PREFIX:
+ *
+ * The parameter name prefix to access 'write' latency histograms. Concatenate
+ * the prefix with either:
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_COUNT
+ * to get the number of bins in given histogram
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_PREFIX and
+ * entry number formatted as an unsigned integer and one of the latency
+ * histogram suffix parameters to compelte a full bin parameter name
+ *
+ * Since: 12.1.0
+ */
+# define VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_WRITE_PREFIX ".latency_histogram.write."
+
+/**
+ * VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_ZONE_APPEND_PREFIX:
+ *
+ * The parameter name prefix to access 'zone_append' latency histograms. Concatenate
+ * the prefix with either:
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_COUNT
+ * to get the number of bins in given histogram
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_PREFIX and
+ * entry number formatted as an unsigned integer and one of the latency
+ * histogram suffix parameters to compelte a full bin parameter name
+ *
+ * Since: 12.1.0
+ */
+# define VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_ZONE_APPEND_PREFIX ".latency_histogram.zone_append."
+
+/**
+ * VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_FLUSH_PREFIX:
+ *
+ * The parameter name prefix to access 'flush' latency histograms. Concatenate
+ * the prefix with either:
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_COUNT
+ * to get the number of bins in given histogram
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_PREFIX and
+ * entry number formatted as an unsigned integer and one of the latency
+ * histogram suffix parameters to compelte a full bin parameter name
+ *
+ * Since: 12.1.0
+ */
+# define VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_FLUSH_PREFIX ".latency_histogram.flush."
+
+/**
+ * VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_COUNT:
+ *
+ * The parameter name suffix to access number of bins in one of the following
+ * latency histogram types:
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_READ_PREFIX
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_WRITE_PREFIX
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_ZONE_APPEND_PREFIX
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_FLUSH_PREFIX
+ *
+ * Number of bins in latency histogram as unsigned long long.
+ *
+ * Since: 12.1.0
+ */
+# define VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_COUNT "bin.count"
+
+/**
+ * VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_PREFIX:
+ *
+ * The parameter name suffix to access a latency histogram bin in one of the
+ * following latency histogram types:
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_READ_PREFIX
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_WRITE_PREFIX
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_ZONE_APPEND_PREFIX
+ * - VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_FLUSH_PREFIX
+ *
+ * Concatenate with a bin number as unsigned int and one of the other field
+ * suffixes to access bin parameters.
+ *
+ * Since: 12.1.0
+ */
+# define VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_PREFIX "bin."
+
+/**
+ * VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_SUFFIX_START:
+ *
+ * Start of the current latency histogram bin in nanoseconds as unsigned long long.
+ *
+ * Since: 12.1.0
+ */
+# define VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_SUFFIX_START ".start"
+
+/**
+ * VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_SUFFIX_VALUE:
+ *
+ * Current value of the number of occurences of the latency within this bin
+ * as unsigned long long.
+ *
+ * Since: 12.1.0
+ */
+# define VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_SUFFIX_VALUE ".value"
+
+
/**
* VIR_DOMAIN_STATS_PERF_CMT:
*
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index cdd333c882..d8cc32eee8 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -17606,6 +17606,36 @@ qemuDomainGetStatsBlockExportBackendStorage(const char *entryname,
}
+static void
+qemuDomainGetStatsBlockExportFrontendLatencyHistogram(struct qemuBlockStatsLatencyHistogram *h,
+ size_t disk_idx,
+ const char *prefix_hist,
+ virTypedParamList *par)
+{
+ size_t i;
+
+ if (!h)
+ return;
+
+ virTypedParamListAddULLong(par, h->nbins,
+ VIR_DOMAIN_STATS_BLOCK_PREFIX "%zu%s" VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_COUNT,
+ disk_idx, prefix_hist);
+
+ for (i = 0; i < h->nbins; i++) {
+ virTypedParamListAddULLong(par, h->bins[i].start,
+ VIR_DOMAIN_STATS_BLOCK_PREFIX "%zu%s"
+ VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_PREFIX "%zu"
+ VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_SUFFIX_START,
+ disk_idx, prefix_hist, i);
+ virTypedParamListAddULLong(par, h->bins[i].value,
+ VIR_DOMAIN_STATS_BLOCK_PREFIX "%zu%s"
+ VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_PREFIX "%zu"
+ VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_SUFFIX_BIN_SUFFIX_VALUE,
+ disk_idx, prefix_hist, i);
+ }
+}
+
+
static void
qemuDomainGetStatsBlockExportFrontend(const char *frontendname,
GHashTable *stats,
@@ -17730,6 +17760,19 @@ qemuDomainGetStatsBlockExportFrontend(const char *frontendname,
idx, i);
}
}
+
+ qemuDomainGetStatsBlockExportFrontendLatencyHistogram(en->histogram_read, idx,
+ VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_READ_PREFIX,
+ par);
+ qemuDomainGetStatsBlockExportFrontendLatencyHistogram(en->histogram_write, idx,
+ VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_WRITE_PREFIX,
+ par);
+ qemuDomainGetStatsBlockExportFrontendLatencyHistogram(en->histogram_zone, idx,
+ VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_ZONE_APPEND_PREFIX,
+ par);
+ qemuDomainGetStatsBlockExportFrontendLatencyHistogram(en->histogram_flush, idx,
+ VIR_DOMAIN_STATS_BLOCK_SUFFIX_LATENCY_HISTOGRAM_FLUSH_PREFIX,
+ par);
}
--
2.52.0© 2016 - 2026 Red Hat, Inc.