perf: add page_faults software perf event support

This patch adds support and documentation
for the page_faults perf event.
Signed-off-by: NNitesh Konkar <nitkon12@linux.vnet.ibm.com>

docs/formatdomain.html.in

@@ -1949,6 +1949,7 @@
   <event name='ref_cpu_cycles' enabled='no'/>
   <event name='cpu_clock' enabled='no'/>
   <event name='task_clock' enabled='no'/>
+  <event name='page_faults' enabled='no'/>
 </perf>
 ...
 </pre>
@@ -2041,6 +2042,13 @@
           is run by applications running on the platform</td>
       <td><code>perf.task_clock</code></td>
     </tr>
+    <tr>
+      <td><code>page_faults</code></td>
+      <td>the count of page faults by applications running on the
+          platform. This includes minor, major, invalid and other
+          types of page faults</td>
+      <td><code>perf.page_faults</code></td>
+    </tr>
   </table>
 
     <h3><a name="elementsDevices">Devices</a></h3>

docs/schemas/domaincommon.rng

@@ -435,6 +435,7 @@
               <value>ref_cpu_cycles</value>
               <value>cpu_clock</value>
               <value>task_clock</value>
+              <value>page_faults</value>
             </choice>
           </attribute>
           <attribute name="enabled">

include/libvirt/libvirt-domain.h

@@ -2210,6 +2210,17 @@ void virDomainStatsRecordListFree(virDomainStatsRecordPtr *stats);
  */
 # define VIR_PERF_PARAM_TASK_CLOCK "task_clock"
 
+/**
+* VIR_PERF_PARAM_PAGE_FAULTS:
+*
+* Macro for typed parameter name that represents page_faults
+* perf event which can be used to measure the count of page
+* faults by applications running on the platform. It corresponds
+* to the "perf.page_faults" field in the *Stats APIs.
+*/
+# define VIR_PERF_PARAM_PAGE_FAULTS "page_faults"
+
+
 int virDomainGetPerfEvents(virDomainPtr dom,
                            virTypedParameterPtr *params,
                            int *nparams,

src/libvirt-domain.c

@@ -11254,6 +11254,8 @@ virConnectGetDomainCapabilities(virConnectPtr conn,
  *                        It is produced by the cpu_clock perf event.
  *     "perf.task_clock" - The count of task clock time as unsigned long long.
  *                         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
  *
  * 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

src/qemu/qemu_driver.c

@@ -9569,6 +9569,7 @@ qemuDomainSetPerfEvents(virDomainPtr dom,
                                VIR_PERF_PARAM_REF_CPU_CYCLES, VIR_TYPED_PARAM_BOOLEAN,
                                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,
                                NULL) < 0)
         return -1;
 

src/util/virperf.c

@@ -44,7 +44,7 @@ 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");
+              "cpu_clock", "task_clock", "page_faults");
 
 struct virPerfEvent {
     int type;
@@ -119,6 +119,9 @@ static struct virPerfEventAttr attrs[] = {
     {.type = VIR_PERF_EVENT_TASK_CLOCK,
      .attrType = PERF_TYPE_SOFTWARE,
      .attrConfig = PERF_COUNT_SW_TASK_CLOCK},
+    {.type = VIR_PERF_EVENT_PAGE_FAULTS,
+     .attrType = PERF_TYPE_SOFTWARE,
+     .attrConfig = PERF_COUNT_SW_PAGE_FAULTS},
 };
 typedef struct virPerfEventAttr *virPerfEventAttrPtr;
 

src/util/virperf.h

@@ -49,6 +49,7 @@ typedef enum {
     VIR_PERF_EVENT_REF_CPU_CYCLES,   /* Count of ref cpu cycles */
     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_LAST
 } virPerfEventType;

tests/genericxml2xmlindata/generic-perf.xml

@@ -28,6 +28,7 @@
     <event name='ref_cpu_cycles' enabled='yes'/>
     <event name='cpu_clock' enabled='yes'/>
     <event name='task_clock' enabled='yes'/>
+    <event name='page_faults' enabled='yes'/>
   </perf>
   <devices>
   </devices>

tools/virsh.pod

@@ -966,6 +966,7 @@ I<--perf> returns the statistics of all enabled perf events:
  "perf.ref_cpu_cycles" - the count of ref cpu cycles
  "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
 
 See the B<perf> command for more details about each event.
 
@@ -2339,6 +2340,8 @@ B<Valid perf event names>
               applications running on the platform.
   task_clock - Provides the task clock time consumed by
                applications running on the platform.
+  page_faults - Provides the count of page faults by
+                applications running on the platform.
 
 B<Note>: The statistics can be retrieved using the B<domstats> command using
 the I<--perf> flag.