perf_cnt: use alternate reporting to minimize logging overhead

Implement simple alternate reporting for perf_cnt_average()
and task_perf_cnt_avg(). By calling the reporting function only
for every other measurement window, the overhead of reporting
can be filtered out from data. This mostly affects the peak
cycle reporting. For average values reporting has only minimal
impact.

Signed-off-by: Kai Vehmanen <[email protected]>

src/include/sof/lib/perf_cnt.h

@@ -95,11 +95,11 @@ struct perf_cnt_data {
 		  (uint32_t)((pcd)->cpu_delta_peak))
 #define task_perf_cnt_avg(pcd, trace_m, arg, class) do {                             \
 		(pcd)->cpu_delta_sum += (pcd)->cpu_delta_last;          \
-		if (++(pcd)->period_cnt == 1 << PERF_CNT_CHECK_WINDOW_SIZE) { \
+		if (!(++(pcd)->period_cnt & MASK(PERF_CNT_CHECK_WINDOW_SIZE - 1, 0))) { \
 			(pcd)->cpu_delta_sum >>= PERF_CNT_CHECK_WINDOW_SIZE;      \
-			trace_m(pcd, arg, class);                                 \
+			if ((pcd)->period_cnt & BIT(PERF_CNT_CHECK_WINDOW_SIZE)) \
+				trace_m(pcd, arg, class);			\
 			(pcd)->cpu_delta_sum = 0;                                 \
-			(pcd)->period_cnt = 0;                                    \
 			(pcd)->plat_delta_peak = 0;                               \
 			(pcd)->cpu_delta_peak = 0;                                \
 		}                                                             \
@@ -115,11 +115,13 @@ struct perf_cnt_data {
  */
 #define perf_cnt_average(pcd, trace_m, arg) do {                             \
 		(pcd)->cpu_delta_sum += (pcd)->cpu_delta_last;               \
-		if (++(pcd)->period_cnt == 1 << PERF_CNT_CHECK_WINDOW_SIZE) {\
+		if (!(++(pcd)->period_cnt & MASK(PERF_CNT_CHECK_WINDOW_SIZE - 1, 0))) { \
 			(pcd)->cpu_delta_sum >>= PERF_CNT_CHECK_WINDOW_SIZE; \
-			trace_m(pcd, arg);                                   \
+			(pcd)->peak_mcps_period_cnt &= MASK(PERF_CNT_CHECK_WINDOW_SIZE - 1, 0); \
+			if ((pcd)->period_cnt & BIT(PERF_CNT_CHECK_WINDOW_SIZE)) { \
+				trace_m(pcd, arg);                                 \
+			} \
 			(pcd)->cpu_delta_sum = 0;                            \
-			(pcd)->period_cnt = 0;                               \
 			(pcd)->plat_delta_peak = 0;                          \
 			(pcd)->cpu_delta_peak = 0;                           \
 			(pcd)->peak_mcps_period_cnt = 0;			     \