| Message ID | 20220523150722.349700-1-pbonzini@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | qmp, hmp: statistics subsystem and KVM suport. | expand |
Paolo Bonzini <pbonzini@redhat.com> writes: > From: Mark Kanda <mark.kanda@oracle.com> > > Gathering statistics is important for development, for monitoring and > for performance measurement. There are tools such as kvm_stat that do > this and they rely on the _user_ knowing the interesting data points > rather than the tool (which can treat them as opaque). > > The commands introduced in this commit introduce QMP support for > querying stats; the goal is to take the capabilities of these tools > and making them available throughout the whole virtualization stack, > so that one can observe, monitor and measure virtual machines without > having shell access + root on the host that runs them. > > query-stats returns a list of all stats per target type (only VM > and vCPU to start); future commits add extra options for specifying > stat names, vCPU qom paths, and providers. All these are used by the > HMP command "info stats". Because of the development usecases around > statistics, a good HMP interface is important. > > query-stats-schemas returns a list of stats included in each target > type, with an option for specifying the provider. The concepts in the > schema are based on the KVM binary stats' own introspection data, just > translated to QAPI. > > There are two reasons to have a separate schema that is not tied to > the QAPI schema. The first is the contents of the schemas: the new > introspection data provides different information than the QAPI data, > namely unit of measurement, how the numbers are gathered and change > (peak/instant/cumulative/histogram), and histogram bucket sizes. > There's really no reason to have this kind of metadata in the QAPI > introspection schema (except possibly for the unit of measure, but > there's a very weak justification). > > Another reason is the dynamicity of the schema. The QAPI introspection > data is very much static; and while QOM is somewhat more dynamic, > generally we consider that to be a bug rather than a feature these days. > On the other hand, the statistics that are exposed by QEMU might be > passed through from another source, such as KVM, and the disadvantages of > manually updating the QAPI schema for outweight the benefits from vetting > the statistics and filtering out anything that seems "too unstable". > Running old QEMU with new kernel is a supported usecase; if old QEMU > cannot expose statistics from a new kernel, or if a kernel developer > needs to change QEMU before gathering new info from the new kernel, > then that is a poor user interface. > > The framework provides a method to register callbacks for these QMP > commands. Most of the work in fact is done by the callbacks, and a > large majority of this patch is new QAPI structs and commands. > > Examples (with KVM stats): > > - Query all VM stats: > > { "execute": "query-stats", "arguments" : { "target": "vm" } } > > { "return": [ > { "provider": "kvm", > "stats": [ > { "name": "max_mmu_page_hash_collisions", "value": 0 }, > { "name": "max_mmu_rmap_size", "value": 0 }, > { "name": "nx_lpage_splits", "value": 148 }, > ... ] }, > { "provider": "xyz", > "stats": [ ... ] } > ] } > > - Query all vCPU stats: > > { "execute": "query-stats", "arguments" : { "target": "vcpu" } } > > { "return": [ > { "provider": "kvm", > "qom_path": "/machine/unattached/device[0]" > "stats": [ > { "name": "guest_mode", "value": 0 }, > { "name": "directed_yield_successful", "value": 0 }, > { "name": "directed_yield_attempted", "value": 106 }, > ... ] }, > { "provider": "kvm", > "qom_path": "/machine/unattached/device[1]" > "stats": [ > { "name": "guest_mode", "value": 0 }, > { "name": "directed_yield_successful", "value": 0 }, > { "name": "directed_yield_attempted", "value": 106 }, > ... ] }, > ] } > > - Retrieve the schemas: > > { "execute": "query-stats-schemas" } > > { "return": [ > { "provider": "kvm", > "target": "vcpu", > "stats": [ > { "name": "guest_mode", > "unit": "none", > "base": 10, > "exponent": 0, > "type": "instant" }, > { "name": "directed_yield_successful", > "unit": "none", > "base": 10, > "exponent": 0, > "type": "cumulative" }, > ... ] > }, > { "provider": "kvm", > "target": "vm", > "stats": [ > { "name": "max_mmu_page_hash_collisions", > "unit": "none", > "base": 10, > "exponent": 0, > "type": "peak" }, > ... ] > }, > { "provider": "xyz", > "target": "vm", > "stats": [ ... ] > } > ] } > > Signed-off-by: Mark Kanda <mark.kanda@oracle.com> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > v3->v4: correctly handle errors from the callbacks > > include/monitor/stats.h | 34 +++++++ > monitor/qmp-cmds.c | 82 +++++++++++++++ > qapi/meson.build | 1 + > qapi/qapi-schema.json | 1 + > qapi/stats.json | 215 ++++++++++++++++++++++++++++++++++++++++ > 5 files changed, 333 insertions(+) > create mode 100644 include/monitor/stats.h > create mode 100644 qapi/stats.json > > diff --git a/include/monitor/stats.h b/include/monitor/stats.h > new file mode 100644 > index 0000000000..912eeadb2f > --- /dev/null > +++ b/include/monitor/stats.h > @@ -0,0 +1,34 @@ > +/* > + * Copyright (c) 2022 Oracle and/or its affiliates. > + * > + * This work is licensed under the terms of the GNU GPL, version 2. > + * See the COPYING file in the top-level directory. > + */ > + > +#ifndef STATS_H > +#define STATS_H > + > +#include "qapi/qapi-types-stats.h" > + > +typedef void StatRetrieveFunc(StatsResultList **result, StatsTarget target, > + Error **errp); > +typedef void SchemaRetrieveFunc(StatsSchemaList **result, Error **errp); > + > +/* > + * Register callbacks for the QMP query-stats command. > + * > + * @stats_fn: routine to query stats: > + * @schema_fn: routine to query stat schemas: Contracts would be nice. > + */ > +void add_stats_callbacks(StatRetrieveFunc *stats_fn, > + SchemaRetrieveFunc *schemas_fn); > + > +/* > + * Helper routines for adding stats entries to the results lists. > + */ > +void add_stats_entry(StatsResultList **, StatsProvider, const char *id, > + StatsList *stats_list); > +void add_stats_schema(StatsSchemaList **, StatsProvider, StatsTarget, > + StatsSchemaValueList *); > + > +#endif /* STATS_H */ > diff --git a/monitor/qmp-cmds.c b/monitor/qmp-cmds.c > index 1ebb89f46c..d65c5f0257 100644 > --- a/monitor/qmp-cmds.c > +++ b/monitor/qmp-cmds.c > @@ -35,6 +35,7 @@ > #include "qapi/qapi-commands-control.h" > #include "qapi/qapi-commands-machine.h" > #include "qapi/qapi-commands-misc.h" > +#include "qapi/qapi-commands-stats.h" > #include "qapi/qapi-commands-ui.h" > #include "qapi/type-helpers.h" > #include "qapi/qmp/qerror.h" > @@ -43,6 +44,7 @@ > #include "hw/acpi/acpi_dev_interface.h" > #include "hw/intc/intc.h" > #include "hw/rdma/rdma.h" > +#include "monitor/stats.h" > > NameInfo *qmp_query_name(Error **errp) > { > @@ -441,3 +443,83 @@ HumanReadableText *qmp_x_query_irq(Error **errp) > > return human_readable_text_from_str(buf); > } > + > +typedef struct StatsCallbacks { > + StatRetrieveFunc *stats_cb; > + SchemaRetrieveFunc *schemas_cb; > + QTAILQ_ENTRY(StatsCallbacks) next; > +} StatsCallbacks; > + > +static QTAILQ_HEAD(, StatsCallbacks) stats_callbacks = > + QTAILQ_HEAD_INITIALIZER(stats_callbacks); > + > +void add_stats_callbacks(StatRetrieveFunc *stats_fn, > + SchemaRetrieveFunc *schemas_fn) > +{ > + StatsCallbacks *entry = g_new(StatsCallbacks, 1); > + entry->stats_cb = stats_fn; > + entry->schemas_cb = schemas_fn; > + > + QTAILQ_INSERT_TAIL(&stats_callbacks, entry, next); > +} > + > +StatsResultList *qmp_query_stats(StatsFilter *filter, Error **errp) > +{ > + StatsResultList *stats_results = NULL; > + StatsCallbacks *entry; > + ERRP_GUARD(); > + > + QTAILQ_FOREACH(entry, &stats_callbacks, next) { > + entry->stats_cb(&stats_results, filter->target, errp); > + if (*errp) { > + qapi_free_StatsResultList(stats_results); > + return NULL; > + } > + } > + > + return stats_results; > +} > + > +StatsSchemaList *qmp_query_stats_schemas(Error **errp) > +{ > + StatsSchemaList *stats_results = NULL; > + StatsCallbacks *entry; > + ERRP_GUARD(); > + > + QTAILQ_FOREACH(entry, &stats_callbacks, next) { > + entry->schemas_cb(&stats_results, errp); > + if (*errp) { > + qapi_free_StatsSchemaList(stats_results); > + return NULL; > + } > + } > + > + return stats_results; > +} Have you considered making the callbacks return bool, following error.h's "Whenever practical, also return a value that indicates success / failure" recommendation? > + > +void add_stats_entry(StatsResultList **stats_results, StatsProvider provider, > + const char *qom_path, StatsList *stats_list) > +{ > + StatsResult *entry = g_new0(StatsResult, 1); > + > + entry->provider = provider; > + if (qom_path) { > + entry->has_qom_path = true; > + entry->qom_path = g_strdup(qom_path); > + } > + entry->stats = stats_list; > + > + QAPI_LIST_PREPEND(*stats_results, entry); > +} > + > +void add_stats_schema(StatsSchemaList **schema_results, > + StatsProvider provider, StatsTarget target, > + StatsSchemaValueList *stats_list) > +{ > + StatsSchema *entry = g_new0(StatsSchema, 1); > + > + entry->provider = provider; > + entry->target = target; > + entry->stats = stats_list; > + QAPI_LIST_PREPEND(*schema_results, entry); > +} > diff --git a/qapi/meson.build b/qapi/meson.build > index 656ef0e039..fd5c93d643 100644 > --- a/qapi/meson.build > +++ b/qapi/meson.build > @@ -46,6 +46,7 @@ qapi_all_modules = [ > 'replay', > 'run-state', > 'sockets', > + 'stats', > 'trace', > 'transaction', > 'yank', > diff --git a/qapi/qapi-schema.json b/qapi/qapi-schema.json > index 4912b9744e..92d7ecc52c 100644 > --- a/qapi/qapi-schema.json > +++ b/qapi/qapi-schema.json > @@ -93,3 +93,4 @@ > { 'include': 'audio.json' } > { 'include': 'acpi.json' } > { 'include': 'pci.json' } > +{ 'include': 'stats.json' } > diff --git a/qapi/stats.json b/qapi/stats.json > new file mode 100644 > index 0000000000..650d883297 > --- /dev/null > +++ b/qapi/stats.json > @@ -0,0 +1,215 @@ > +# -*- Mode: Python -*- > +# vim: filetype=python > +# > +# Copyright (c) 2022 Oracle and/or its affiliates. > +# > +# This work is licensed under the terms of the GNU GPL, version 2 or later. > +# See the COPYING file in the top-level directory. > +# > +# SPDX-License-Identifier: GPL-2.0-or-later > + > +## > +# = Statistics > +## > + > +## > +# @StatsType: > +# > +# Enumeration of statistics types > +# > +# @cumulative: stat is cumulative; value can only increase. > +# @instant: stat is instantaneous; value can increase or decrease. > +# @peak: stat is the peak value; value can only increase. > +# @linear-histogram: stat is a linear histogram. > +# @log2-histogram: stat is a logarithmic histogram, with one bucket > +# for each power of two. > +# > +# Since: 7.1 > +## > +{ 'enum' : 'StatsType', > + 'data' : [ 'cumulative', 'instant', 'peak', 'linear-histogram', 'log2-histogram' ] } Long line. > + > +## > +# @StatsUnit: > +# > +# Enumeration of unit of measurement for statistics > +# > +# @bytes: stat reported in bytes. > +# @seconds: stat reported in seconds. > +# @cycles: stat reported in clock cycles. > +# > +# Since: 7.1 > +## > +{ 'enum' : 'StatsUnit', > + 'data' : [ 'bytes', 'seconds', 'cycles' ] } > + > +## > +# @StatsProvider: > +# > +# Enumeration of statistics providers. > +# > +# Since: 7.1 > +## > +{ 'enum': 'StatsProvider', > + 'data': [ ] } > + > +## > +# @StatsTarget: > +# > +# The kinds of objects on which one can request statistics. > +# > +# @vm: statistics that apply to the entire virtual machine or > +# the entire QEMU process. > +# > +# @vcpu: statistics that apply to a single virtual CPU. > +# > +# Since: 7.1 > +## > +{ 'enum': 'StatsTarget', > + 'data': [ 'vm', 'vcpu' ] } > + > +## > +# @StatsFilter: > +# > +# The arguments to the query-stats command; specifies a target for which to > +# request statistics. > +# > +# Since: 7.1 > +## > +{ 'struct': 'StatsFilter', > + 'data': { 'target': 'StatsTarget' } } > + > +## > +# @StatsValue: > +# > +# @scalar: single unsigned 64-bit integers. > +# @list: list of unsigned 64-bit integers (used for histograms). > +# > +# Since: 7.1 > +## > +{ 'alternate': 'StatsValue', > + 'data': { 'scalar': 'uint64', > + 'list': [ 'uint64' ] } } > + > +## > +# @Stats: > +# > +# @name: name of stat. > +# @value: stat value. > +# > +# Since: 7.1 > +## > +{ 'struct': 'Stats', > + 'data': { 'name': 'str', > + 'value' : 'StatsValue' } } > + > +## > +# @StatsResult: > +# > +# @provider: provider for this set of statistics. > +# > +# @qom-path: Path to the object for which the statistics are returned, > +# if the object is exposed in the QOM tree > +# > +# @stats: list of statistics. > +# > +# Since: 7.1 > +## > +{ 'struct': 'StatsResult', > + 'data': { 'provider': 'StatsProvider', > + '*qom-path': 'str', > + 'stats': [ 'Stats' ] } } > + > +## > +# @query-stats: > +# > +# Return runtime-collected statistics for objects such as the > +# VM or its vCPUs. > +# > +# The arguments are a StatsFilter and specify the provider and objects > +# to return statistics about. > +# > +# Returns: a list of StatsResult, one for each provider and object > +# (e.g., for each vCPU). > +# > +# Since: 7.1 > +## > +{ 'command': 'query-stats', > + 'data': 'StatsFilter', > + 'boxed': true, > + 'returns': [ 'StatsResult' ] } > + > +## > +# @StatsSchemaValue: > +# > +# Schema for a single statistic. > +# > +# @name: name of the statistic; each element of the schema is uniquely > +# identified by a target, a provider (both available in @StatsSchema) > +# and the name. > +# > +# @type: kind of statistic. > +# > +# @unit: basic unit of measure for the statistic; if missing, the statistic > +# is a simple number or counter. > +# > +# @base: base for the multiple of @unit in which the statistic is measured. > +# Only present if @exponent is non-zero; @base and @exponent together > +# form a SI prefix (e.g., _nano-_ for ``base=10`` and ``exponent=-9``) > +# or IEC binary prefix (e.g. _kibi-_ for ``base=2`` and ``exponent=10``) > +# > +# @exponent: exponent for the multiple of @unit in which the statistic is > +# expressed, or 0 for the basic unit > +# > +# @bucket-size: Present when @type is "linear-histogram", contains the width > +# of each bucket of the histogram. > +# > +# Since: 7.1 > +## > +{ 'struct': 'StatsSchemaValue', > + 'data': { 'name': 'str', > + 'type': 'StatsType', > + '*unit': 'StatsUnit', > + '*base': 'int8', > + 'exponent': 'int16', > + '*bucket-size': 'uint32' } } > + > +## > +# @StatsSchema: > +# > +# Schema for all available statistics for a provider and target. > +# > +# @provider: provider for this set of statistics. > +# > +# @target: the kind of object that can be queried through the provider. > +# > +# @stats: list of statistics. > +# > +# Since: 7.1 > +## > +{ 'struct': 'StatsSchema', > + 'data': { 'provider': 'StatsProvider', > + 'target': 'StatsTarget', > + 'stats': [ 'StatsSchemaValue' ] } } > + > +## > +# @query-stats-schemas: > +# > +# Return the schema for all available runtime-collected statistics. > +# > +# Note: runtime-collected statistics and their names fall outside QEMU's > +# usual deprecation policies. QEMU will try to keep the set of available > +# data stable, together with their names, but will not guarantee stability > +# at all costs; the same is true of providers that source statistics > +# externally, e.g. from Linux. For example, if the same value is being > +# tracked with different names on different architectures or by different > +# providers, one of them might be renamed. A statistic might go away if > +# an algorithm is changed or some code is removed; changing a default might > +# cause previously useful statistics to always report 0. Such changes, > +# however, are expected to be rare. > +# > +# Since: 7.1 > +## > +{ 'command': 'query-stats-schemas', > + 'data': { }, > + 'returns': [ 'StatsSchema' ] } With the long line wrapped: Reviewed-by: Markus Armbruster <armbru@redhat.com>
[...] > diff --git a/qapi/stats.json b/qapi/stats.json > new file mode 100644 > index 0000000000..650d883297 > --- /dev/null > +++ b/qapi/stats.json [...] > +## > +# @query-stats-schemas: > +# > +# Return the schema for all available runtime-collected statistics. > +# > +# Note: runtime-collected statistics and their names fall outside QEMU's > +# usual deprecation policies. QEMU will try to keep the set of available /work/armbru/qemu/scripts/qapi-gen.py: In file included from ../qapi/qapi-schema.json:96: ../qapi/stats.json:201:1: unexpected de-indent (expected at least 6 spaces) > +# data stable, together with their names, but will not guarantee stability > +# at all costs; the same is true of providers that source statistics > +# externally, e.g. from Linux. For example, if the same value is being > +# tracked with different names on different architectures or by different > +# providers, one of them might be renamed. A statistic might go away if > +# an algorithm is changed or some code is removed; changing a default might > +# cause previously useful statistics to always report 0. Such changes, > +# however, are expected to be rare. > +# > +# Since: 7.1 > +## > +{ 'command': 'query-stats-schemas', > + 'data': { }, > + 'returns': [ 'StatsSchema' ] }
On 5/24/22 12:41, Markus Armbruster wrote: >> + return stats_results; >> +} > Have you considered making the callbacks return bool, following > error.h's "Whenever practical, also return a value that indicates > success / failure" recommendation? > No, because I generally do not consider that recommendation to apply to callbacks. Callbacks are written many times and typically invoked just once, so I prefer an O(1) loss in convenience to an O(n) chance of making a mistake in the return value. Paolo
diff --git a/include/monitor/stats.h b/include/monitor/stats.h new file mode 100644 index 0000000000..912eeadb2f --- /dev/null +++ b/include/monitor/stats.h @@ -0,0 +1,34 @@ +/* + * Copyright (c) 2022 Oracle and/or its affiliates. + * + * This work is licensed under the terms of the GNU GPL, version 2. + * See the COPYING file in the top-level directory. + */ + +#ifndef STATS_H +#define STATS_H + +#include "qapi/qapi-types-stats.h" + +typedef void StatRetrieveFunc(StatsResultList **result, StatsTarget target, + Error **errp); +typedef void SchemaRetrieveFunc(StatsSchemaList **result, Error **errp); + +/* + * Register callbacks for the QMP query-stats command. + * + * @stats_fn: routine to query stats: + * @schema_fn: routine to query stat schemas: + */ +void add_stats_callbacks(StatRetrieveFunc *stats_fn, + SchemaRetrieveFunc *schemas_fn); + +/* + * Helper routines for adding stats entries to the results lists. + */ +void add_stats_entry(StatsResultList **, StatsProvider, const char *id, + StatsList *stats_list); +void add_stats_schema(StatsSchemaList **, StatsProvider, StatsTarget, + StatsSchemaValueList *); + +#endif /* STATS_H */ diff --git a/monitor/qmp-cmds.c b/monitor/qmp-cmds.c index 1ebb89f46c..d65c5f0257 100644 --- a/monitor/qmp-cmds.c +++ b/monitor/qmp-cmds.c @@ -35,6 +35,7 @@ #include "qapi/qapi-commands-control.h" #include "qapi/qapi-commands-machine.h" #include "qapi/qapi-commands-misc.h" +#include "qapi/qapi-commands-stats.h" #include "qapi/qapi-commands-ui.h" #include "qapi/type-helpers.h" #include "qapi/qmp/qerror.h" @@ -43,6 +44,7 @@ #include "hw/acpi/acpi_dev_interface.h" #include "hw/intc/intc.h" #include "hw/rdma/rdma.h" +#include "monitor/stats.h" NameInfo *qmp_query_name(Error **errp) { @@ -441,3 +443,83 @@ HumanReadableText *qmp_x_query_irq(Error **errp) return human_readable_text_from_str(buf); } + +typedef struct StatsCallbacks { + StatRetrieveFunc *stats_cb; + SchemaRetrieveFunc *schemas_cb; + QTAILQ_ENTRY(StatsCallbacks) next; +} StatsCallbacks; + +static QTAILQ_HEAD(, StatsCallbacks) stats_callbacks = + QTAILQ_HEAD_INITIALIZER(stats_callbacks); + +void add_stats_callbacks(StatRetrieveFunc *stats_fn, + SchemaRetrieveFunc *schemas_fn) +{ + StatsCallbacks *entry = g_new(StatsCallbacks, 1); + entry->stats_cb = stats_fn; + entry->schemas_cb = schemas_fn; + + QTAILQ_INSERT_TAIL(&stats_callbacks, entry, next); +} + +StatsResultList *qmp_query_stats(StatsFilter *filter, Error **errp) +{ + StatsResultList *stats_results = NULL; + StatsCallbacks *entry; + ERRP_GUARD(); + + QTAILQ_FOREACH(entry, &stats_callbacks, next) { + entry->stats_cb(&stats_results, filter->target, errp); + if (*errp) { + qapi_free_StatsResultList(stats_results); + return NULL; + } + } + + return stats_results; +} + +StatsSchemaList *qmp_query_stats_schemas(Error **errp) +{ + StatsSchemaList *stats_results = NULL; + StatsCallbacks *entry; + ERRP_GUARD(); + + QTAILQ_FOREACH(entry, &stats_callbacks, next) { + entry->schemas_cb(&stats_results, errp); + if (*errp) { + qapi_free_StatsSchemaList(stats_results); + return NULL; + } + } + + return stats_results; +} + +void add_stats_entry(StatsResultList **stats_results, StatsProvider provider, + const char *qom_path, StatsList *stats_list) +{ + StatsResult *entry = g_new0(StatsResult, 1); + + entry->provider = provider; + if (qom_path) { + entry->has_qom_path = true; + entry->qom_path = g_strdup(qom_path); + } + entry->stats = stats_list; + + QAPI_LIST_PREPEND(*stats_results, entry); +} + +void add_stats_schema(StatsSchemaList **schema_results, + StatsProvider provider, StatsTarget target, + StatsSchemaValueList *stats_list) +{ + StatsSchema *entry = g_new0(StatsSchema, 1); + + entry->provider = provider; + entry->target = target; + entry->stats = stats_list; + QAPI_LIST_PREPEND(*schema_results, entry); +} diff --git a/qapi/meson.build b/qapi/meson.build index 656ef0e039..fd5c93d643 100644 --- a/qapi/meson.build +++ b/qapi/meson.build @@ -46,6 +46,7 @@ qapi_all_modules = [ 'replay', 'run-state', 'sockets', + 'stats', 'trace', 'transaction', 'yank', diff --git a/qapi/qapi-schema.json b/qapi/qapi-schema.json index 4912b9744e..92d7ecc52c 100644 --- a/qapi/qapi-schema.json +++ b/qapi/qapi-schema.json @@ -93,3 +93,4 @@ { 'include': 'audio.json' } { 'include': 'acpi.json' } { 'include': 'pci.json' } +{ 'include': 'stats.json' } diff --git a/qapi/stats.json b/qapi/stats.json new file mode 100644 index 0000000000..650d883297 --- /dev/null +++ b/qapi/stats.json @@ -0,0 +1,215 @@ +# -*- Mode: Python -*- +# vim: filetype=python +# +# Copyright (c) 2022 Oracle and/or its affiliates. +# +# This work is licensed under the terms of the GNU GPL, version 2 or later. +# See the COPYING file in the top-level directory. +# +# SPDX-License-Identifier: GPL-2.0-or-later + +## +# = Statistics +## + +## +# @StatsType: +# +# Enumeration of statistics types +# +# @cumulative: stat is cumulative; value can only increase. +# @instant: stat is instantaneous; value can increase or decrease. +# @peak: stat is the peak value; value can only increase. +# @linear-histogram: stat is a linear histogram. +# @log2-histogram: stat is a logarithmic histogram, with one bucket +# for each power of two. +# +# Since: 7.1 +## +{ 'enum' : 'StatsType', + 'data' : [ 'cumulative', 'instant', 'peak', 'linear-histogram', 'log2-histogram' ] } + +## +# @StatsUnit: +# +# Enumeration of unit of measurement for statistics +# +# @bytes: stat reported in bytes. +# @seconds: stat reported in seconds. +# @cycles: stat reported in clock cycles. +# +# Since: 7.1 +## +{ 'enum' : 'StatsUnit', + 'data' : [ 'bytes', 'seconds', 'cycles' ] } + +## +# @StatsProvider: +# +# Enumeration of statistics providers. +# +# Since: 7.1 +## +{ 'enum': 'StatsProvider', + 'data': [ ] } + +## +# @StatsTarget: +# +# The kinds of objects on which one can request statistics. +# +# @vm: statistics that apply to the entire virtual machine or +# the entire QEMU process. +# +# @vcpu: statistics that apply to a single virtual CPU. +# +# Since: 7.1 +## +{ 'enum': 'StatsTarget', + 'data': [ 'vm', 'vcpu' ] } + +## +# @StatsFilter: +# +# The arguments to the query-stats command; specifies a target for which to +# request statistics. +# +# Since: 7.1 +## +{ 'struct': 'StatsFilter', + 'data': { 'target': 'StatsTarget' } } + +## +# @StatsValue: +# +# @scalar: single unsigned 64-bit integers. +# @list: list of unsigned 64-bit integers (used for histograms). +# +# Since: 7.1 +## +{ 'alternate': 'StatsValue', + 'data': { 'scalar': 'uint64', + 'list': [ 'uint64' ] } } + +## +# @Stats: +# +# @name: name of stat. +# @value: stat value. +# +# Since: 7.1 +## +{ 'struct': 'Stats', + 'data': { 'name': 'str', + 'value' : 'StatsValue' } } + +## +# @StatsResult: +# +# @provider: provider for this set of statistics. +# +# @qom-path: Path to the object for which the statistics are returned, +# if the object is exposed in the QOM tree +# +# @stats: list of statistics. +# +# Since: 7.1 +## +{ 'struct': 'StatsResult', + 'data': { 'provider': 'StatsProvider', + '*qom-path': 'str', + 'stats': [ 'Stats' ] } } + +## +# @query-stats: +# +# Return runtime-collected statistics for objects such as the +# VM or its vCPUs. +# +# The arguments are a StatsFilter and specify the provider and objects +# to return statistics about. +# +# Returns: a list of StatsResult, one for each provider and object +# (e.g., for each vCPU). +# +# Since: 7.1 +## +{ 'command': 'query-stats', + 'data': 'StatsFilter', + 'boxed': true, + 'returns': [ 'StatsResult' ] } + +## +# @StatsSchemaValue: +# +# Schema for a single statistic. +# +# @name: name of the statistic; each element of the schema is uniquely +# identified by a target, a provider (both available in @StatsSchema) +# and the name. +# +# @type: kind of statistic. +# +# @unit: basic unit of measure for the statistic; if missing, the statistic +# is a simple number or counter. +# +# @base: base for the multiple of @unit in which the statistic is measured. +# Only present if @exponent is non-zero; @base and @exponent together +# form a SI prefix (e.g., _nano-_ for ``base=10`` and ``exponent=-9``) +# or IEC binary prefix (e.g. _kibi-_ for ``base=2`` and ``exponent=10``) +# +# @exponent: exponent for the multiple of @unit in which the statistic is +# expressed, or 0 for the basic unit +# +# @bucket-size: Present when @type is "linear-histogram", contains the width +# of each bucket of the histogram. +# +# Since: 7.1 +## +{ 'struct': 'StatsSchemaValue', + 'data': { 'name': 'str', + 'type': 'StatsType', + '*unit': 'StatsUnit', + '*base': 'int8', + 'exponent': 'int16', + '*bucket-size': 'uint32' } } + +## +# @StatsSchema: +# +# Schema for all available statistics for a provider and target. +# +# @provider: provider for this set of statistics. +# +# @target: the kind of object that can be queried through the provider. +# +# @stats: list of statistics. +# +# Since: 7.1 +## +{ 'struct': 'StatsSchema', + 'data': { 'provider': 'StatsProvider', + 'target': 'StatsTarget', + 'stats': [ 'StatsSchemaValue' ] } } + +## +# @query-stats-schemas: +# +# Return the schema for all available runtime-collected statistics. +# +# Note: runtime-collected statistics and their names fall outside QEMU's +# usual deprecation policies. QEMU will try to keep the set of available +# data stable, together with their names, but will not guarantee stability +# at all costs; the same is true of providers that source statistics +# externally, e.g. from Linux. For example, if the same value is being +# tracked with different names on different architectures or by different +# providers, one of them might be renamed. A statistic might go away if +# an algorithm is changed or some code is removed; changing a default might +# cause previously useful statistics to always report 0. Such changes, +# however, are expected to be rare. +# +# Since: 7.1 +## +{ 'command': 'query-stats-schemas', + 'data': { }, + 'returns': [ 'StatsSchema' ] }