lib: os: mpsc_pbuf: Add usage tracking

Add API to fetch current buffer usage. Add option to track
maximum buffer usage and API to fetch that value.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>

include/sys/mpsc_pbuf.h

@@ -58,6 +58,9 @@ extern "C" {
  */
 #define MPSC_PBUF_MODE_OVERWRITE BIT(1)
 
+/** @brief Flag indicating that maximum buffer usage is tracked. */
+#define MPSC_PBUF_MAX_UTILIZATION BIT(2)
+
 /**@} */
 
 /* Forward declaration */
@@ -112,6 +115,9 @@ struct mpsc_pbuf_buffer {
 	/* Buffer size in 32 bit words. */
 	uint32_t size;
 
+	/* Store max buffer usage. */
+	uint32_t max_usage;
+
 	struct k_sem sem;
 };
 
@@ -237,6 +243,24 @@ void mpsc_pbuf_free(struct mpsc_pbuf_buffer *buffer,
  */
 bool mpsc_pbuf_is_pending(struct mpsc_pbuf_buffer *buffer);
 
+/** @brief Get current memory utilization.
+ *
+ * @param[in, out] buffer Buffer.
+ * @param[out]     size   Buffer size in bytes.
+ * @param[out]     now    Current buffer usage in bytes.
+ */
+void mpsc_pbuf_get_utilization(struct mpsc_pbuf_buffer *buffer,
+			       uint32_t *size, uint32_t *now);
+
+/** @brief Get maximum memory utilization.
+ *
+ * @param[in, out] buffer Buffer.
+ * @param[out]     max    Maximum buffer usage in bytes.
+ *
+ * retval 0 if utilization data collected successfully.
+ * retval -ENOTSUP if Collecting utilization data is not supported.
+ */
+int mpsc_pbuf_get_max_utilization(struct mpsc_pbuf_buffer *buffer, uint32_t *max);
 /**
  * @}
  */

lib/os/mpsc_pbuf.c

@@ -35,6 +35,7 @@ void mpsc_pbuf_init(struct mpsc_pbuf_buffer *buffer,
 	buffer->notify_drop = cfg->notify_drop;
 	buffer->buf = cfg->buf;
 	buffer->size = cfg->size;
+	buffer->max_usage = 0;
 	buffer->flags = cfg->flags;
 
 	if (is_power_of_two(buffer->size)) {
@@ -74,6 +75,26 @@ static inline bool available(struct mpsc_pbuf_buffer *buffer, uint32_t *res)
 	return true;
 }
 
+static inline uint32_t get_usage(struct mpsc_pbuf_buffer *buffer)
+{
+	uint32_t f;
+
+	if (free_space(buffer, &f)) {
+		f += (buffer->rd_idx - 1);
+	}
+
+	return buffer->size - 1 - f;
+}
+
+static inline void max_utilization_update(struct mpsc_pbuf_buffer *buffer)
+{
+	if (!(buffer->flags & MPSC_PBUF_MAX_UTILIZATION)) {
+		return;
+	}
+
+	buffer->max_usage = MAX(buffer->max_usage, get_usage(buffer));
+}
+
 static inline bool is_valid(union mpsc_pbuf_generic *item)
 {
 	return item->hdr.valid;
@@ -190,6 +211,7 @@ void mpsc_pbuf_put_word(struct mpsc_pbuf_buffer *buffer,
 			buffer->tmp_wr_idx = idx_inc(buffer,
 						     buffer->tmp_wr_idx, 1);
 			buffer->wr_idx = idx_inc(buffer, buffer->wr_idx, 1);
+			max_utilization_update(buffer);
 		} else {
 			bool user_drop = buffer->flags & MPSC_PBUF_MODE_OVERWRITE;
 
@@ -288,6 +310,7 @@ void mpsc_pbuf_commit(struct mpsc_pbuf_buffer *buffer,
 
 	item->hdr.valid = 1;
 	buffer->wr_idx = idx_inc(buffer, buffer->wr_idx, wlen);
+	max_utilization_update(buffer);
 	k_spin_unlock(&buffer->lock, key);
 	MPSC_PBUF_DBG(buffer, "committed %p ", item);
 }
@@ -320,6 +343,7 @@ void mpsc_pbuf_put_word_ext(struct mpsc_pbuf_buffer *buffer,
 			buffer->tmp_wr_idx =
 				idx_inc(buffer, buffer->tmp_wr_idx, l);
 			buffer->wr_idx = idx_inc(buffer, buffer->wr_idx, l);
+			max_utilization_update(buffer);
 		} else if (wrap) {
 			add_skip_item(buffer, free_wlen);
 			cont = true;
@@ -363,6 +387,7 @@ void mpsc_pbuf_put_data(struct mpsc_pbuf_buffer *buffer, const uint32_t *data,
 			buffer->tmp_wr_idx =
 				idx_inc(buffer, buffer->tmp_wr_idx, wlen);
 			buffer->wr_idx = idx_inc(buffer, buffer->wr_idx, wlen);
+			max_utilization_update(buffer);
 		} else if (wrap) {
 			add_skip_item(buffer, free_wlen);
 			cont = true;
@@ -460,3 +485,22 @@ bool mpsc_pbuf_is_pending(struct mpsc_pbuf_buffer *buffer)
 
 	return a ? true : false;
 }
+
+void mpsc_pbuf_get_utilization(struct mpsc_pbuf_buffer *buffer,
+			       uint32_t *size, uint32_t *now)
+{
+	/* One byte is left for full/empty distinction. */
+	*size = (buffer->size - 1) * sizeof(int);
+	*now = get_usage(buffer) * sizeof(int);
+}
+
+int mpsc_pbuf_get_max_utilization(struct mpsc_pbuf_buffer *buffer, uint32_t *max)
+{
+
+	if (!(buffer->flags & MPSC_PBUF_MAX_UTILIZATION)) {
+		return -ENOTSUP;
+	}
+
+	*max = buffer->max_usage * sizeof(int);
+	return 0;
+}