[libvirt] [PATCH v2 04/10] perf: add context_switches software perf event support
Nitesh Konkar
niteshkonkar.libvirt at gmail.com
Thu Feb 23 14:55:33 UTC 2017
This patch adds support and documentation
for the context_switches perf event.
Signed-off-by: Nitesh Konkar <nitkon12 at linux.vnet.ibm.com>
---
docs/formatdomain.html.in | 7 +++++++
docs/schemas/domaincommon.rng | 1 +
include/libvirt/libvirt-domain.h | 10 ++++++++++
src/libvirt-domain.c | 3 +++
src/qemu/qemu_driver.c | 1 +
src/util/virperf.c | 6 +++++-
src/util/virperf.h | 1 +
tests/genericxml2xmlindata/generic-perf.xml | 1 +
tools/virsh.pod | 3 +++
9 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index 72d33fa..bff699f 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -1939,6 +1939,7 @@
<event name='cpu_clock' enabled='no'/>
<event name='task_clock' enabled='no'/>
<event name='page_faults' enabled='no'/>
+ <event name='context_switches' enabled='no'/>
</perf>
...
</pre>
@@ -2038,6 +2039,12 @@
types of page faults</td>
<td><code>perf.page_faults</code></td>
</tr>
+ <tr>
+ <td><code>context_switches</code></td>
+ <td>the count of context switches by applications running on
+ the platform</td>
+ <td><code>perf.context_switches</code></td>
+ </tr>
</table>
<h3><a name="elementsDevices">Devices</a></h3>
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 856a2f7..1a4b6cb 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -436,6 +436,7 @@
<value>cpu_clock</value>
<value>task_clock</value>
<value>page_faults</value>
+ <value>context_switches</value>
</choice>
</attribute>
<attribute name="enabled">
diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
index 1a6cb19..f7e4cd2 100644
--- a/include/libvirt/libvirt-domain.h
+++ b/include/libvirt/libvirt-domain.h
@@ -2220,6 +2220,16 @@ void virDomainStatsRecordListFree(virDomainStatsRecordPtr *stats);
*/
# define VIR_PERF_PARAM_PAGE_FAULTS "page_faults"
+/**
+ * VIR_PERF_PARAM_CONTEXT_SWITCHES:
+ *
+ * Macro for typed parameter name that represents context_switches
+ * perf event which can be used to measure the count of context
+ * switches by applications running on the platform. It corresponds
+ * to the "perf.context_switches" field in the *Stats APIs.
+ */
+# define VIR_PERF_PARAM_CONTEXT_SWITCHES "context_switches"
+
int virDomainGetPerfEvents(virDomainPtr dom,
virTypedParameterPtr *params,
diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
index 77c6e8a..6b29d14 100644
--- a/src/libvirt-domain.c
+++ b/src/libvirt-domain.c
@@ -11256,6 +11256,9 @@ virConnectGetDomainCapabilities(virConnectPtr conn,
* It is produced by the task_clock perf event.
* "perf.page_faults" - The count of page faults as unsigned long long.
* It is produced by the page_faults perf event
+ * "perf.context_switches" - The count of context switches as unsigned long
+ * long. It is produced by the context_switches
+ * perf event.
*
* Note that entire stats groups or individual stat fields may be missing from
* the output in case they are not supported by the given hypervisor, are not
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 10d4e59..8d6df1a 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -9572,6 +9572,7 @@ qemuDomainSetPerfEvents(virDomainPtr dom,
VIR_PERF_PARAM_CPU_CLOCK, VIR_TYPED_PARAM_BOOLEAN,
VIR_PERF_PARAM_TASK_CLOCK, VIR_TYPED_PARAM_BOOLEAN,
VIR_PERF_PARAM_PAGE_FAULTS, VIR_TYPED_PARAM_BOOLEAN,
+ VIR_PERF_PARAM_CONTEXT_SWITCHES, VIR_TYPED_PARAM_BOOLEAN,
NULL) < 0)
return -1;
diff --git a/src/util/virperf.c b/src/util/virperf.c
index 4ae13af..ba81e08 100644
--- a/src/util/virperf.c
+++ b/src/util/virperf.c
@@ -44,7 +44,8 @@ VIR_ENUM_IMPL(virPerfEvent, VIR_PERF_EVENT_LAST,
"branch_instructions", "branch_misses",
"bus_cycles", "stalled_cycles_frontend",
"stalled_cycles_backend", "ref_cpu_cycles",
- "cpu_clock", "task_clock", "page_faults");
+ "cpu_clock", "task_clock", "page_faults",
+ "context_switches");
struct virPerfEvent {
int type;
@@ -122,6 +123,9 @@ static struct virPerfEventAttr attrs[] = {
{.type = VIR_PERF_EVENT_PAGE_FAULTS,
.attrType = PERF_TYPE_SOFTWARE,
.attrConfig = PERF_COUNT_SW_PAGE_FAULTS},
+ {.type = VIR_PERF_EVENT_CONTEXT_SWITCHES,
+ .attrType = PERF_TYPE_SOFTWARE,
+ .attrConfig = PERF_COUNT_SW_CONTEXT_SWITCHES},
};
typedef struct virPerfEventAttr *virPerfEventAttrPtr;
diff --git a/src/util/virperf.h b/src/util/virperf.h
index 182a9ec..2adc549 100644
--- a/src/util/virperf.h
+++ b/src/util/virperf.h
@@ -50,6 +50,7 @@ typedef enum {
VIR_PERF_EVENT_CPU_CLOCK, /* Count of cpu clock time*/
VIR_PERF_EVENT_TASK_CLOCK, /* Count of task clock time*/
VIR_PERF_EVENT_PAGE_FAULTS, /* Count of total page faults */
+ VIR_PERF_EVENT_CONTEXT_SWITCHES, /* Count of context switches */
VIR_PERF_EVENT_LAST
} virPerfEventType;
diff --git a/tests/genericxml2xmlindata/generic-perf.xml b/tests/genericxml2xmlindata/generic-perf.xml
index 3f27887..29a2273 100644
--- a/tests/genericxml2xmlindata/generic-perf.xml
+++ b/tests/genericxml2xmlindata/generic-perf.xml
@@ -29,6 +29,7 @@
<event name='cpu_clock' enabled='yes'/>
<event name='task_clock' enabled='yes'/>
<event name='page_faults' enabled='yes'/>
+ <event name='context_switches' enabled='yes'/>
</perf>
<devices>
</devices>
diff --git a/tools/virsh.pod b/tools/virsh.pod
index 81fd0fb..eb7c255 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -967,6 +967,7 @@ I<--perf> returns the statistics of all enabled perf events:
"perf.cpu_clock" - the count of cpu clock time
"perf.task_clock" - the count of task clock time
"perf.page_faults" - the count of page faults
+ "perf.context_switches" - the count of context switches.
See the B<perf> command for more details about each event.
@@ -2342,6 +2343,8 @@ B<Valid perf event names>
applications running on the platform.
page_faults - Provides the count of page faults by
applications running on the platform
+ context_switches - Provides the count of context switches
+ by applications running on the platform
B<Note>: The statistics can be retrieved using the B<domstats> command using
the I<--perf> flag.
--
1.9.3
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