qemu/include/monitor/stats.h
Paolo Bonzini cf7405bc02 qmp: add filtering of statistics by name
Allow retrieving only a subset of statistics.  This can be useful
for example in order to plot a subset of the statistics many times
a second: KVM publishes ~40 statistics for each vCPU on x86; retrieving
and serializing all of them would be useless.

Another use will be in HMP in the following patch; implementing the
filter in the backend is easy enough that it was deemed okay to make
this a public interface.

Example:

{ "execute": "query-stats",
  "arguments": {
    "target": "vcpu",
    "vcpus": [ "/machine/unattached/device[2]",
               "/machine/unattached/device[4]" ],
    "providers": [
      { "provider": "kvm",
        "names": [ "l1d_flush", "exits" ] } } }

{ "return": {
    "vcpus": [
      { "path": "/machine/unattached/device[2]"
        "providers": [
          { "provider": "kvm",
            "stats": [ { "name": "l1d_flush", "value": 41213 },
                       { "name": "exits", "value": 74291 } ] } ] },
      { "path": "/machine/unattached/device[4]"
        "providers": [
          { "provider": "kvm",
            "stats": [ { "name": "l1d_flush", "value": 16132 },
                       { "name": "exits", "value": 57922 } ] } ] } ] } }

Extracted from a patch by Mark Kanda.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-14 16:50:30 +02:00

46 lines
1.4 KiB
C

/*
* 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,
strList *names, strList *targets, Error **errp);
typedef void SchemaRetrieveFunc(StatsSchemaList **result, Error **errp);
/*
* Register callbacks for the QMP query-stats command.
*
* @provider: stats provider checked against QMP command arguments
* @stats_fn: routine to query stats:
* @schema_fn: routine to query stat schemas:
*/
void add_stats_callbacks(StatsProvider provider,
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 *);
/*
* True if a string matches the filter passed to the stats_fn callabck,
* false otherwise.
*
* Note that an empty list means no filtering, i.e. all strings will
* return true.
*/
bool apply_str_list_filter(const char *string, strList *list);
#endif /* STATS_H */