fpsi: mutexless mode

pikvm · Mar 30, 2024 · 3a3889d · 3a3889d
1 parent 88203f9
commit 3a3889d
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Showing 2 changed files with 41 additions and 17 deletions.
diff --git a/src/libs/fpsi.c b/src/libs/fpsi.c
@@ -22,6 +22,8 @@
 
 #include "fpsi.h"
 
+#include <stdatomic.h>
+
 #include <pthread.h>
 
 #include "types.h"
@@ -36,33 +38,47 @@ us_fpsi_s *us_fpsi_init(const char *name, bool with_meta) {
 	US_CALLOC(fpsi, 1);
 	fpsi->name = us_strdup(name);
 	fpsi->with_meta = with_meta;
-	US_MUTEX_INIT(fpsi->mutex);
+	atomic_init(&fpsi->ts, 0);
+	atomic_init(&fpsi->current, 0);
+	if (with_meta) {
+		US_MUTEX_INIT(fpsi->mutex);
+	}
 	return fpsi;
 }
 
 void us_fpsi_destroy(us_fpsi_s *fpsi) {
-	US_MUTEX_DESTROY(fpsi->mutex);
+	if (fpsi->with_meta) {
+		US_MUTEX_DESTROY(fpsi->mutex);
+	}
 	free(fpsi->name);
 	free(fpsi);
 }
 
 void us_fpsi_bump(us_fpsi_s *fpsi, const us_frame_s *frame) {
-	US_MUTEX_LOCK(fpsi->mutex);
+	if (frame != NULL) {
+		assert(fpsi->with_meta);
+	} else {
+		assert(!fpsi->with_meta);
+	}
+
+	if (fpsi->with_meta) {
+		US_MUTEX_LOCK(fpsi->mutex);
+	}
+
 	const sll now_sec_ts = us_floor_ms(us_get_now_monotonic());
-	if (fpsi->ts != now_sec_ts) {
+	if (atomic_load(&fpsi->ts) != now_sec_ts) {
 		US_LOG_PERF_FPS("FPS: %s: %u", fpsi->name, fpsi->accum);
-		fpsi->current = fpsi->accum;
+		atomic_store(&fpsi->current, fpsi->accum);
+		atomic_store(&fpsi->ts, now_sec_ts);
 		fpsi->accum = 0;
-		fpsi->ts = now_sec_ts;
 	}
 	++fpsi->accum;
-	if (frame != NULL) {
-		assert(fpsi->with_meta);
+
+	if (fpsi->with_meta) {
+		assert(frame != NULL);
 		US_FRAME_COPY_META(frame, &fpsi->meta);
-	} else {
-		assert(!fpsi->with_meta);
+		US_MUTEX_UNLOCK(fpsi->mutex);
 	}
-	US_MUTEX_UNLOCK(fpsi->mutex);
 }
 
 uint us_fpsi_get(us_fpsi_s *fpsi, us_fpsi_meta_s *meta) {
@@ -71,12 +87,18 @@ uint us_fpsi_get(us_fpsi_s *fpsi, us_fpsi_meta_s *meta) {
 	} else {
 		assert(!fpsi->with_meta);
 	}
-	US_MUTEX_LOCK(fpsi->mutex);
+
+	if (fpsi->with_meta) {
+		US_MUTEX_LOCK(fpsi->mutex);
+	}
+
 	const sll now_sec_ts = us_floor_ms(us_get_now_monotonic());
-	const uint current = (fpsi->ts == now_sec_ts ? fpsi->current : 0);
-	if (meta != NULL) {
+	const uint current = (atomic_load(&fpsi->ts) == now_sec_ts ? fpsi->current : 0);
+
+	if (fpsi->with_meta) {
+		assert(meta != NULL);
 		US_FRAME_COPY_META(&fpsi->meta, meta);
+		US_MUTEX_UNLOCK(fpsi->mutex);
 	}
-	US_MUTEX_UNLOCK(fpsi->mutex);
 	return current;
 }
diff --git a/src/libs/fpsi.h b/src/libs/fpsi.h
@@ -22,6 +22,8 @@
 
 #pragma once
 
+#include <stdatomic.h>
+
 #include <pthread.h>
 
 #include "types.h"
@@ -36,8 +38,8 @@ typedef struct {
 	char			*name;
 	bool			with_meta;
 	uint			accum;
-	ldf				ts;
-	uint			current;
+	atomic_llong	ts;
+	atomic_uint		current;
 	us_fpsi_meta_s	meta;
 	pthread_mutex_t	mutex;
 } us_fpsi_s;