docs: Alter descriptions of perf cpu_cycles

https://bugzilla.redhat.com/show_bug.cgi?id=1381714

Alter the descriptions to match what the cpu_cycles actually is

docs/formatdomain.html.in

@@ -1954,7 +1954,7 @@
     </tr>
     <tr>
       <td><code>cpu_cycles</code></td>
-      <td>the number of cpu cycles one instruction needs</td>
+      <td>the count of cpu cycles (total/elapsed)</td>
       <td><code>perf.cpu_cycles</code></td>
     </tr>
     <tr>

include/libvirt/libvirt-domain.h

@@ -2008,7 +2008,8 @@ void virDomainStatsRecordListFree(virDomainStatsRecordPtr *stats);
  * VIR_PERF_PARAM_CPU_CYCLES:
  *
  * Macro for typed parameter name that represents cpu_cycles perf event
- * which can be used to measure how many cpu cycles one instruction needs.
+ * describing the total/elapsed cpu cycles. This can be used to measure
+ * how many cpu cycles one instruction needs.
  * It corresponds to the "perf.cpu_cycles" field in the *Stats APIs.
  */
 # define VIR_PERF_PARAM_CPU_CYCLES "cpu_cycles"

src/libvirt-domain.c

@@ -11482,7 +11482,7 @@ virConnectGetDomainCapabilities(virConnectPtr conn,
  *                           It is produced by cache_references perf event.
  * "perf.instructions"     - The count of instructions as unsigned long long.
  *                           It is produced by instructions perf event.
- * "perf.cpu_cycles"       - The number of cpu cycles one instruction needs as
+ * "perf.cpu_cycles"       - The count of cpu cycles (total/elapsed) as an
  *                           unsigned long long. It is produced by cpu_cycles
  *                           perf event.
  *

src/util/virperf.h

@@ -32,7 +32,7 @@ typedef enum {
     VIR_PERF_EVENT_MBMT,   /* Memory Bandwidth Monitoring Total */
     VIR_PERF_EVENT_MBML,   /* Memory Bandwidth Monitor Limit for controller */
 
-    VIR_PERF_EVENT_CPU_CYCLES,       /* CPU Cycles per instruction */
+    VIR_PERF_EVENT_CPU_CYCLES,       /* Count of CPU Cycles (total/elapsed) */
     VIR_PERF_EVENT_INSTRUCTIONS,     /* Count of instructions for application */
     VIR_PERF_EVENT_CACHE_REFERENCES, /* Cache hits by applications */
     VIR_PERF_EVENT_CACHE_MISSES,     /* Cache misses by applications */

tools/virsh.pod

@@ -934,7 +934,7 @@ I<--perf> returns the statistics of all enabled perf events:
 "perf.cmt" - the cache usage in Byte currently used
 "perf.mbmt" - total system bandwidth from one level of cache
 "perf.mbml" - bandwidth of memory traffic for a memory controller
-"perf.cpu_cycles" - the number of cpu cycles one instruction needs
+"perf.cpu_cycles" - the count of cpu cycles (total/elapsed)
 "perf.instructions" - the count of instructions
 "perf.cache_references" - the count of cache hits
 "perf.cache_misses" - the count of caches misses
@@ -2247,9 +2247,10 @@ B<Valid perf event names>
                      applications running on th e platform.
   instructions     - Provides the count of instructions executed
                      by applications running on the platform.
-  cpu_cycles       - Provides the number of cpu_cycles for one
-                     instruction. May be used with instructions
-                     in order to get a cycles per instruction.
+  cpu_cycles       - Provides the count of cpu cycles
+                     (total/elapsed). May be used with
+                     instructions in order to get a cycles
+                     per instruction.
 
 B<Note>: The statistics can be retrieved using the B<domstats> command using
 the I<--perf> flag.