Add statistic to rtems_disk_device and bdbuf

[Xiang Cui]

Hi

I want to add new struct to the rtems_disk_device and bdbuf. All of
them are counters for read/write and cache hit number. This is a very
basic ideal now. These change will help to measure the IO performance
and uncover the bdbuf state.

All these statistics will be updated in bdbuf, I think.

The changes in bdbuf.h and diskdevs.h may like this.

diff --git a/cpukit/libblock/include/rtems/bdbuf.h
b/cpukit/libblock/include/rtems/bdbuf.h
index 134a0ce..25ad374 100644
--- a/cpukit/libblock/include/rtems/bdbuf.h
+++ b/cpukit/libblock/include/rtems/bdbuf.h
@@ -292,6 +292,18 @@ typedef enum
 } rtems_bdbuf_buf_state;

 /**
+* @brief Statistic for bdbuf.
+*/
+typedef struct {
+  unsigned swapout_execute_count;   /**< counter for swapout execute */
+  unsigned recycle_count;           /**< counter for the recycle */
+  unsigned total_write_count;       /**< counter for the total write action */
+  unsigned total_read_count;        /**< counter for the total read action */
+  unsigned total_write_hit;         /**< counter for the total write hit  */
+  unsigned total_read_hit;          /**< counter for the total read hit */
+} rtems_bdbuf_statistic;
+
+/**
  * Forward reference to the block.
  */
 struct rtems_bdbuf_group;
@@ -644,6 +656,14 @@ rtems_bdbuf_purge_dev (const rtems_disk_device *dd);
 rtems_status_code
 rtems_bdbuf_set_block_size (rtems_disk_device *dd, uint32_t block_size);

+
+/**
+* @brief Return the statistic for bdbuf.
+*
+* @return pointer to rtems_bdbuf_statistic.
+*/
+const rtems_bdbuf_statistic *rtems_bdbuf_get_statistic(void);
+
 /** @} */

 #ifdef __cplusplus
diff --git a/cpukit/libblock/include/rtems/diskdevs.h
b/cpukit/libblock/include/rtems/diskdevs.h
index 2e3f753..e969894 100644
--- a/cpukit/libblock/include/rtems/diskdevs.h
+++ b/cpukit/libblock/include/rtems/diskdevs.h
@@ -55,6 +55,30 @@ typedef int (*rtems_block_device_ioctl)(
 );

 /**
+ * @brief Statistic to count the write and read number for bdbuf.
+ *
+ * These statistics counted by block size.
+ */
+typedef struct {
+  /**
+  * @brief counter for write number since the disk device was created
+  */
+  unsigned write_count;
+  /**
+  * @brief counter for read number since the disk device was created
+  */
+  unsigned read_count;
+  /**
+  * @brief counter for write hit in bdbuf
+  */
+  unsigned write_hit;
+  /**
+  * @brief counter for read hit in bdbuf
+  */
+  unsigned read_hit;
+} rtems_disk_device_statistic;
+
+/**
  * @brief Description of a disk device (logical and physical disks).
  *
  * An array of pointer tables to rtems_disk_device structures is maintained.
@@ -153,6 +177,13 @@ struct rtems_disk_device {
    * releases this disk.
    */
   bool deleted;
+
+ /**
+  * @brief statistic for disk device. The logical disks have the same
+  * pointer to these physical disk.
+  */
+  rtems_disk_device_statistic *statistic;
+
 };

 /**
@@ -217,6 +248,12 @@ static inline rtems_blkdev_bnum rtems_disk_get_block_count(
   return dd->size;
 }

+static inline rtems_disk_device_statistic *
+rtems_disk_get_statistic( const rtems_disk_device *dd)
+{
+  return dd->statistic;
+}
+
 /** @} */

 /**