libblock: Add block device statistics

cpukit/libblock/Makefile.am

@@ -7,6 +7,8 @@ libblock_a_SOURCES = src/bdbuf.c \
     src/blkdev-imfs.c \
     src/blkdev-ioctl.c \
     src/blkdev-ops.c \
+    src/blkdev-print-stats.c \
+    src/blkdev-blkstats.c \
     src/diskdevs.c \
     src/diskdevs-init.c \
     src/flashdisk.c \

cpukit/libblock/include/rtems/bdbuf.h

@@ -662,6 +662,19 @@ rtems_bdbuf_purge_dev (rtems_disk_device *dd);
 rtems_status_code
 rtems_bdbuf_set_block_size (rtems_disk_device *dd, uint32_t block_size);
 
+/**
+ * @brief Returns the block device statistics.
+ */
+void
+rtems_bdbuf_get_device_stats (const rtems_disk_device *dd,
+                              rtems_blkdev_stats      *stats);
+
+/**
+ * @brief Resets the block device statistics.
+ */
+void
+rtems_bdbuf_reset_device_stats (rtems_disk_device *dd);
+
 /** @} */
 
 #ifdef __cplusplus

cpukit/libblock/include/rtems/blkdev.h

@@ -16,7 +16,9 @@
 
 #include <rtems.h>
 #include <rtems/diskdevs.h>
+#include <rtems/bspIo.h>
 #include <sys/ioctl.h>
+#include <stdio.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -161,6 +163,8 @@ typedef struct rtems_blkdev_request {
 #define RTEMS_BLKIO_CAPABILITIES    _IO('B', 8)
 #define RTEMS_BLKIO_GETDISKDEV      _IOR('B', 9, rtems_disk_device *)
 #define RTEMS_BLKIO_PURGEDEV        _IO('B', 10)
+#define RTEMS_BLKIO_GETDEVSTATS     _IOR('B', 11, rtems_blkdev_stats *)
+#define RTEMS_BLKIO_RESETDEVSTATS   _IO('B', 12)
 
 /** @} */
 
@@ -208,6 +212,19 @@ static inline int rtems_disk_fd_purge(int fd)
   return ioctl(fd, RTEMS_BLKIO_PURGEDEV);
 }
 
+static inline int rtems_disk_fd_get_device_stats(
+  int fd,
+  rtems_blkdev_stats *stats
+)
+{
+  return ioctl(fd, RTEMS_BLKIO_GETDEVSTATS, stats);
+}
+
+static inline int rtems_disk_fd_reset_device_stats(int fd)
+{
+  return ioctl(fd, RTEMS_BLKIO_RESETDEVSTATS);
+}
+
 /**
  * Only consecutive multi-sector buffer requests are supported.
  *
@@ -361,6 +378,24 @@ rtems_status_code rtems_blkdev_create_partition(
   rtems_blkdev_bnum block_count
 );
 
+/**
+ * @brief Prints the block device statistics.
+ */
+void rtems_blkdev_print_stats(
+  const rtems_blkdev_stats *stats,
+  rtems_printk_plugin_t print,
+  void *print_arg
+);
+
+/**
+ * @brief Block device statistics command.
+ */
+void rtems_blkstats(
+  FILE *output,
+  const char *device,
+  bool reset
+);
+
 /** @} */
 
 #ifdef __cplusplus

cpukit/libblock/include/rtems/diskdevs.h

@@ -86,6 +86,68 @@ typedef struct {
   rtems_blkdev_bnum next;
 } rtems_blkdev_read_ahead;
 
+/**
+ * @brief Block device statistics.
+ *
+ * Integer overflows in the statistic counters may happen.
+ */
+typedef struct {
+  /**
+   * @brief Read hit count.
+   * 
+   * A read hit occurs in the rtems_bdbuf_read() function in case the block is
+   * in the cached or modified state.
+   */
+  uint32_t read_hits;
+
+  /**
+   * @brief Read miss count.
+   * 
+   * A read miss occurs in the rtems_bdbuf_read() function in case the block is
+   * in the empty state and a read transfer must be initiated to read the data
+   * from the device.
+   */
+  uint32_t read_misses;
+
+  /**
+   * @brief Read-ahead transfer count.
+   *
+   * Each read-ahead transfer may read multiple blocks.
+   */
+  uint32_t read_ahead_transfers;
+
+  /**
+   * @brief Count of blocks transfered from the device.
+   */
+  uint32_t read_blocks;
+
+  /**
+   * @brief Read error count.
+   *
+   * Error count of transfers issued by the read or read-ahead requests.
+   */
+  uint32_t read_errors;
+
+  /**
+   * @brief Write transfer count.
+   *
+   * Each write transfer may write multiple blocks.
+   */
+  uint32_t write_transfers;
+
+  /**
+   * @brief Count of blocks transfered to the device.
+   */
+  uint32_t write_blocks;
+
+  /**
+   * @brief Write error count.
+   *
+   * Error count of transfers issued by write requests.
+   */
+  uint32_t write_errors;
+} rtems_blkdev_stats;
+
 /**
  * @brief Description of a disk device (logical and physical disks).
  *
@@ -201,6 +263,11 @@ struct rtems_disk_device {
    */
   bool deleted;
 
+  /**
+   * @brief Device statistics for this disk.
+   */
+  rtems_blkdev_stats stats;
+
   /**
    * @brief Read-ahead control for this disk.
    */

cpukit/libblock/src/bdbuf.c

@@ -1899,6 +1899,21 @@ rtems_bdbuf_execute_transfer_request (rtems_disk_device    *dd,
 
   rtems_bdbuf_lock_cache ();
 
+  /* Statistics */
+  if (req->req == RTEMS_BLKDEV_REQ_READ)
+  {
+    dd->stats.read_blocks += req->bufnum;
+    if (sc != RTEMS_SUCCESSFUL)
+      ++dd->stats.read_errors;
+  }
+  else
+  {
+    dd->stats.write_blocks += req->bufnum;
+    ++dd->stats.write_transfers;
+    if (sc != RTEMS_SUCCESSFUL)
+      ++dd->stats.write_errors;
+  }
+
   for (transfer_index = 0; transfer_index < req->bufnum; ++transfer_index)
   {
     rtems_bdbuf_buffer *bd = req->bufs [transfer_index].user;
@@ -2074,12 +2089,15 @@ rtems_bdbuf_read (rtems_disk_device   *dd,
     switch (bd->state)
     {
       case RTEMS_BDBUF_STATE_CACHED:
+        ++dd->stats.read_hits;
         rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_ACCESS_CACHED);
         break;
       case RTEMS_BDBUF_STATE_MODIFIED:
+        ++dd->stats.read_hits;
         rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_ACCESS_MODIFIED);
         break;
       case RTEMS_BDBUF_STATE_EMPTY:
+        ++dd->stats.read_misses;
         rtems_bdbuf_set_read_ahead_trigger (dd, block);
         sc = rtems_bdbuf_execute_read_request (dd, bd, 1);
         if (sc == RTEMS_SUCCESSFUL)
@@ -3025,6 +3043,7 @@ rtems_bdbuf_read_ahead_task (rtems_task_argument arg)
             dd->read_ahead.trigger = RTEMS_DISK_READ_AHEAD_NO_TRIGGER;
           }
 
+          ++dd->stats.read_ahead_transfers;
           rtems_bdbuf_execute_read_request (dd, bd, transfer_count);
         }
       }
@@ -3039,3 +3058,18 @@ rtems_bdbuf_read_ahead_task (rtems_task_argument arg)
 
   rtems_task_delete (RTEMS_SELF);
 }
+
+void rtems_bdbuf_get_device_stats (const rtems_disk_device *dd,
+                                   rtems_blkdev_stats      *stats)
+{
+  rtems_bdbuf_lock_cache ();
+  *stats = dd->stats;
+  rtems_bdbuf_unlock_cache ();
+}
+
+void rtems_bdbuf_reset_device_stats (rtems_disk_device *dd)
+{
+  rtems_bdbuf_lock_cache ();
+  memset (&dd->stats, 0, sizeof(dd->stats));
+  rtems_bdbuf_unlock_cache ();
+}

cpukit/libblock/src/blkdev-blkstats.c

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2012 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Obere Lagerstr. 30
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.com/license/LICENSE.
+ */
+
+#if HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#include <rtems/blkdev.h>
+
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+
+void rtems_blkstats(FILE *output, const char *device, bool reset)
+{
+  int fd = open(device, O_RDONLY);
+
+  if (fd >= 0) {
+    struct stat st;
+    int rv;
+
+    rv = fstat(fd, &st);
+    if (rv == 0) {
+      if (S_ISBLK(st.st_mode)) {
+        if (reset) {
+          rv = rtems_disk_fd_reset_device_stats(fd);
+          if (rv != 0) {
+            fprintf(output, "error: reset stats: %s\n", strerror(errno));
+          }
+        } else {
+          rtems_blkdev_stats stats;
+
+          rv = rtems_disk_fd_get_device_stats(fd, &stats);
+          if (rv == 0) {
+            rtems_blkdev_print_stats(
+              &stats,
+              (rtems_printk_plugin_t) fprintf,
+              output
+            );
+          } else {
+            fprintf(output, "error: get stats: %s\n", strerror(errno));
+          }
+        }
+      } else {
+        fprintf(output, "error: not a block device\n");
+      }
+    } else {
+      fprintf(output, "error: get file stats: %s\n", strerror(errno));
+    }
+
+    rv = close(fd);
+    if (rv != 0) {
+      fprintf(output, "error: close device: %s\n", strerror(errno));
+    }
+  } else {
+    fprintf(output, "error: open device: %s\n", strerror(errno));
+  }
+}

cpukit/libblock/src/blkdev-ioctl.c

@@ -64,6 +64,14 @@ rtems_blkdev_ioctl(rtems_disk_device *dd, uint32_t req, void *argp)
             rtems_bdbuf_purge_dev(dd);
             break;
 
+        case RTEMS_BLKIO_GETDEVSTATS:
+            rtems_bdbuf_get_device_stats(dd, (rtems_blkdev_stats *) argp);
+            break;
+
+        case RTEMS_BLKIO_RESETDEVSTATS:
+            rtems_bdbuf_reset_device_stats(dd);
+            break;
+
         default:
             errno = EINVAL;
             rc = -1;

cpukit/libblock/src/blkdev-print-stats.c

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2012 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Obere Lagerstr. 30
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.com/license/LICENSE.
+ */
+
+#if HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#include <rtems/blkdev.h>
+
+#include <inttypes.h>
+
+void rtems_blkdev_print_stats(
+  const rtems_blkdev_stats *stats,
+  rtems_printk_plugin_t print,
+  void *print_arg
+)
+{
+  (*print)(
+     print_arg,
+     "-------------------------------------------------------------------------------\n"
+     "                               DEVICE STATISTICS\n"
+     "----------------------+--------------------------------------------------------\n"
+     " READ HITS            | %" PRIu32 "\n"
+     " READ MISSES          | %" PRIu32 "\n"
+     " READ AHEAD TRANSFERS | %" PRIu32 "\n"
+     " READ BLOCKS          | %" PRIu32 "\n"
+     " READ ERRORS          | %" PRIu32 "\n"
+     " WRITE TRANSFERS      | %" PRIu32 "\n"
+     " WRITE BLOCKS         | %" PRIu32 "\n"
+     " WRITE ERRORS         | %" PRIu32 "\n"
+     "----------------------+--------------------------------------------------------\n",
+     stats->read_hits,
+     stats->read_misses,
+     stats->read_ahead_transfers,
+     stats->read_blocks,
+     stats->read_errors,
+     stats->write_transfers,
+     stats->write_blocks,
+     stats->write_errors
+  );
+}