perf: add stalled_cycles_frontend perf event support

This patch adds support and documentation
for the stalled_cycles_frontend perf event.

Signed-off-by: Nitesh Konkar <nitkon12@linux.vnet.ibm.com>

src/libvirt-domain.c

@@ -11236,6 +11236,11 @@ virConnectGetDomainCapabilities(virConnectPtr conn,
  *                            long. It is produced by branch_misses perf event.
  *     "perf.bus_cycles" - The count of bus cycles as unsigned long
  *                         long. It is produced by bus_cycles perf event.
+ *     "perf.stalled_cycles_frontend" - The count of stalled cpu cycles in the
+ *                                      frontend of the instruction processor
+ *                                      pipeline as unsigned long long. It is
+ *                                      produced by stalled_cycles_frontend
+ *                                      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

@@ -9856,6 +9856,7 @@ qemuDomainSetPerfEvents(virDomainPtr dom,
                                VIR_PERF_PARAM_BRANCH_INSTRUCTIONS, VIR_TYPED_PARAM_BOOLEAN,
                                VIR_PERF_PARAM_BRANCH_MISSES, VIR_TYPED_PARAM_BOOLEAN,
                                VIR_PERF_PARAM_BUS_CYCLES, VIR_TYPED_PARAM_BOOLEAN,
+                               VIR_PERF_PARAM_STALLED_CYCLES_FRONTEND, VIR_TYPED_PARAM_BOOLEAN,
                                NULL) < 0)
         return -1;
 

src/util/virperf.c

@@ -42,7 +42,7 @@ VIR_ENUM_IMPL(virPerfEvent, VIR_PERF_EVENT_LAST,
               "cpu_cycles", "instructions",
               "cache_references", "cache_misses",
               "branch_instructions", "branch_misses",
-              "bus_cycles");
+              "bus_cycles", "stalled_cycles_frontend");
 
 struct virPerfEvent {
     int type;
@@ -96,6 +96,9 @@ static struct virPerfEventAttr attrs[] = {
     {.type = VIR_PERF_EVENT_BUS_CYCLES,
      .attrType = PERF_TYPE_HARDWARE,
      .attrConfig = PERF_COUNT_HW_BUS_CYCLES},
+    {.type = VIR_PERF_EVENT_STALLED_CYCLES_FRONTEND,
+     .attrType = PERF_TYPE_HARDWARE,
+     .attrConfig = PERF_COUNT_HW_STALLED_CYCLES_FRONTEND},
 };
 typedef struct virPerfEventAttr *virPerfEventAttrPtr;
 

src/util/virperf.h

@@ -40,6 +40,9 @@ typedef enum {
                                            for applications */
     VIR_PERF_EVENT_BRANCH_MISSES,  /* Count of branch misses for applications */
     VIR_PERF_EVENT_BUS_CYCLES,       /* Count of bus cycles for applications*/
+    VIR_PERF_EVENT_STALLED_CYCLES_FRONTEND, /* Count of stalled cpu cycles in
+                                               the frontend of the instruction
+                                               processor pipeline */
 
     VIR_PERF_EVENT_LAST
 } virPerfEventType;