Enable support for ref-cycles perf counter in QtTestLib.

The ref-cycles counter corresponds to the monotonic timestamp counter
that can be read using the RDTSC assembler instruction. Using it
instead of the default cycles counter is useful as it removes the
effect of dynamic frequency scaling on the measurement.

[ChangeLog][QtTest] The ref-cycles perf counter can now be used.

Change-Id: Id7d56576db362706c20f9a399e5acea35ee799f2
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

3 files changed, 13 insertions, 4 deletions

diff --git a/src/testlib/qbenchmarkmetric.cpp b/src/testlib/qbenchmarkmetric.cpp
index 0a9072907f..0ba55dbeb7 100644
--- a/src/testlib/qbenchmarkmetric.cpp
+++ b/src/testlib/qbenchmarkmetric.cpp
@@ -56,6 +56,7 @@
   \value CPUTicks               CPU time
   \value CPUMigrations          Process migrations between CPUs
   \value CPUCycles              CPU cycles
+  \value RefCPUCycles           Reference CPU cycles
   \value BusCycles              Bus cycles
   \value StalledCycles          Cycles stalled
   \value InstructionReads       Instruction reads
@@ -108,6 +109,8 @@ const char * QTest::benchmarkMetricName(QBenchmarkMetric metric)
         return "CPUMigrations";
     case CPUCycles:
         return "CPUCycles";
+    case RefCPUCycles:
+        return "RefCPUCycles";
     case BusCycles:
         return "BusCycles";
     case StalledCycles:
@@ -180,6 +183,8 @@ const char * QTest::benchmarkMetricUnit(QBenchmarkMetric metric)
         return "CPU migrations";
     case CPUCycles:
         return "CPU cycles";
+    case RefCPUCycles:
+        return "Reference CPU cycles";
     case BusCycles:
         return "bus cycles";
     case StalledCycles:
diff --git a/src/testlib/qbenchmarkmetric.h b/src/testlib/qbenchmarkmetric.h
index 44bf14b9b6..6e423473b1 100644
--- a/src/testlib/qbenchmarkmetric.h
+++ b/src/testlib/qbenchmarkmetric.h
@@ -78,7 +78,8 @@ enum QBenchmarkMetric {
     MinorPageFaults,
     MajorPageFaults,
     AlignmentFaults,
-    EmulationFaults
+    EmulationFaults,
+    RefCPUCycles,
 };
 
 }
diff --git a/src/testlib/qbenchmarkperfevents.cpp b/src/testlib/qbenchmarkperfevents.cpp
index 587d3e0124..d6db40ce52 100644
--- a/src/testlib/qbenchmarkperfevents.cpp
+++ b/src/testlib/qbenchmarkperfevents.cpp
@@ -153,6 +153,7 @@ bool QBenchmarkPerfEventsMeasurer::isAvailable()
 
    Event type   Event counter           Unit            Name and aliases
    HARDWARE     CPU_CYCLES              CPUCycles       cycles  cpu-cycles
+   HARDWARE     REF_CPU_CYCLES          RefCPUCycles    ref-cycles
    HARDWARE     INSTRUCTIONS            Instructions    instructions
    HARDWARE     CACHE_REFERENCES        CacheReferences cache-references
    HARDWARE     CACHE_MISSES            CacheMisses     cache-misses
@@ -321,6 +322,7 @@ static const char eventlist_strings[] =
     "migrations\0"
     "minor-faults\0"
     "page-faults\0"
+    "ref-cycles\0"
     "stalled-cycles-backend\0"
     "stalled-cycles-frontend\0"
     "task-clock\0"
@@ -407,9 +409,10 @@ static const Events eventlist[] = {
     { 1256, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CPU_MIGRATIONS, QTest::CPUMigrations },
     { 1267, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_PAGE_FAULTS_MIN, QTest::MinorPageFaults },
     { 1280, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_PAGE_FAULTS, QTest::PageFaults },
-    { 1292, PERF_TYPE_HARDWARE, PERF_COUNT_HW_STALLED_CYCLES_BACKEND, QTest::StalledCycles },
-    { 1315, PERF_TYPE_HARDWARE, PERF_COUNT_HW_STALLED_CYCLES_FRONTEND, QTest::StalledCycles },
-    { 1339, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_TASK_CLOCK, QTest::WalltimeMilliseconds },
+    { 1292, PERF_TYPE_HARDWARE, PERF_COUNT_HW_REF_CPU_CYCLES, QTest::RefCPUCycles },
+    { 1303, PERF_TYPE_HARDWARE, PERF_COUNT_HW_STALLED_CYCLES_BACKEND, QTest::StalledCycles },
+    { 1326, PERF_TYPE_HARDWARE, PERF_COUNT_HW_STALLED_CYCLES_FRONTEND, QTest::StalledCycles },
+    { 1350, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_TASK_CLOCK, QTest::WalltimeMilliseconds },
     {   0, PERF_TYPE_MAX, 0, QTest::Events }
 };
 /* -- END GENERATED CODE -- */