[rtems commit] libblock: Add read-ahead task
Sebastian Huber
sebh at rtems.org
Mon Jun 4 07:51:40 UTC 2012
Module: rtems
Branch: master
Commit: 39ee704e757268de833ffb956dda28f6aa2fa3a1
Changeset: http://git.rtems.org/rtems/commit/?id=39ee704e757268de833ffb956dda28f6aa2fa3a1
Author: Sebastian Huber <sebastian.huber at embedded-brains.de>
Date: Thu May 31 10:27:29 2012 +0200
libblock: Add read-ahead task
Read-ahead requests were previously executed in the context of the
reading task. This blocks the reading task until the complete read
with read-ahead transfer is finished. A read-ahead task is introduced
to off-load the read-ahead transfer. This allows the reading task to
work with the requested block more quickly. The read-ahead is triggered
after two misses of ascending consecutive blocks or a read hit of a
block read by the most-recent read-ahead transfer. The read-ahead
feature is configurable and can be disabled.
---
cpukit/libblock/include/rtems/bdbuf.h | 26 ++-
cpukit/libblock/include/rtems/diskdevs.h | 37 ++++
cpukit/libblock/src/bdbuf.c | 347 +++++++++++++++++++-----------
cpukit/libblock/src/diskdevs-init.c | 2 +
cpukit/sapi/include/confdefs.h | 11 +-
testsuites/libtests/Makefile.am | 1 +
testsuites/libtests/block13/Makefile.am | 19 ++
testsuites/libtests/block13/block13.doc | 11 +
testsuites/libtests/block13/block13.scn | 11 +
testsuites/libtests/block13/init.c | 232 ++++++++++++++++++++
testsuites/libtests/configure.ac | 1 +
11 files changed, 568 insertions(+), 130 deletions(-)
diff --git a/cpukit/libblock/include/rtems/bdbuf.h b/cpukit/libblock/include/rtems/bdbuf.h
index 43a95df..5275c13 100644
--- a/cpukit/libblock/include/rtems/bdbuf.h
+++ b/cpukit/libblock/include/rtems/bdbuf.h
@@ -46,7 +46,7 @@ extern "C" {
* @ingroup rtems_libblock
*
* The Block Device Buffer Management implements a cache between the disk
- * devices and file systems. The code provides read ahead and write queuing to
+ * devices and file systems. The code provides read-ahead and write queuing to
* the drivers and fast cache look-up using an AVL tree.
*
* The block size used by a file system can be set at runtime and must be a
@@ -152,10 +152,13 @@ extern "C" {
* written. This would be a performance problem.
*
* The code performs multiple block reads and writes. Multiple block reads or
- * read ahead increases performance with hardware that supports it. It also
+ * read-ahead increases performance with hardware that supports it. It also
* helps with a large cache as the disk head movement is reduced. It however
* is a speculative operation so excessive use can remove valuable and needed
- * blocks from the cache.
+ * blocks from the cache. The read-ahead is triggered after two misses of
+ * ascending consecutive blocks or a read hit of a block read by the
+ * most-resent read-ahead transfer. The read-ahead works per disk, but all
+ * transfers are issued by the read-ahead task.
*
* The cache has the following lists of buffers:
* - LRU: Accessed or transfered buffers released in least recently used
@@ -379,6 +382,8 @@ typedef struct rtems_bdbuf_config {
uint32_t buffer_max; /**< Maximum buffer size
* supported. It is also the
* allocation size. */
+ rtems_task_priority read_ahead_priority; /**< Priority of the read-ahead
+ * task. */
} rtems_bdbuf_config;
/**
@@ -389,8 +394,8 @@ typedef struct rtems_bdbuf_config {
extern const rtems_bdbuf_config rtems_bdbuf_configuration;
/**
- * The max_read_ahead_blocks value is altered if there are fewer buffers
- * than this defined max. This stops thrashing in the cache.
+ * The default value for the maximum read-ahead blocks disables the read-ahead
+ * feature.
*/
#define RTEMS_BDBUF_MAX_READ_AHEAD_BLOCKS_DEFAULT 0
@@ -426,6 +431,12 @@ extern const rtems_bdbuf_config rtems_bdbuf_configuration;
RTEMS_BDBUF_SWAPOUT_TASK_PRIORITY_DEFAULT
/**
+ * Default read-ahead task priority. The same as the swap-out task.
+ */
+#define RTEMS_BDBUF_READ_AHEAD_TASK_PRIORITY_DEFAULT \
+ RTEMS_BDBUF_SWAPOUT_TASK_PRIORITY_DEFAULT
+
+/**
* Default task stack size for swap-out and worker tasks.
*/
#define RTEMS_BDBUF_TASK_STACK_SIZE_DEFAULT RTEMS_MINIMUM_STACK_SIZE
@@ -621,7 +632,7 @@ rtems_bdbuf_syncdev (rtems_disk_device *dd);
/**
* @brief Purges all buffers corresponding to the disk device @a dd.
*
- * This may result in loss of data.
+ * This may result in loss of data. The read-ahead state of this device is reset.
*
* Before you can use this function, the rtems_bdbuf_init() routine must be
* called at least once to initialize the cache, otherwise a fatal error will
@@ -635,7 +646,8 @@ rtems_bdbuf_purge_dev (rtems_disk_device *dd);
/**
* @brief Sets the block size of a disk device.
*
- * This will set the block size derived fields of the disk device.
+ * This will set the block size derived fields of the disk device. The
+ * read-ahead state of this device is reset.
*
* Before you can use this function, the rtems_bdbuf_init() routine must be
* called at least once to initialize the cache, otherwise a fatal error will
diff --git a/cpukit/libblock/include/rtems/diskdevs.h b/cpukit/libblock/include/rtems/diskdevs.h
index fe931f8..0b19409 100644
--- a/cpukit/libblock/include/rtems/diskdevs.h
+++ b/cpukit/libblock/include/rtems/diskdevs.h
@@ -16,6 +16,7 @@
#include <rtems.h>
#include <rtems/libio.h>
+#include <rtems/chain.h>
#include <stdlib.h>
#ifdef __cplusplus
@@ -55,6 +56,37 @@ typedef int (*rtems_block_device_ioctl)(
);
/**
+ * @brief Trigger value to disable further read-ahead requests.
+ */
+#define RTEMS_DISK_READ_AHEAD_NO_TRIGGER ((rtems_blkdev_bnum) -1)
+
+/**
+ * @brief Read-ahead control.
+ */
+typedef struct {
+ /**
+ * @brief Chain node for the read-ahead request queue of the read-ahead task.
+ */
+ rtems_chain_node node;
+
+ /**
+ * @brief Block value to trigger the read-ahead request.
+ *
+ * A value of @ref RTEMS_DISK_READ_AHEAD_NO_TRIGGER will disable further
+ * read-ahead requests since no valid block can have this value.
+ */
+ rtems_blkdev_bnum trigger;
+
+ /**
+ * @brief Start block for the next read-ahead request.
+ *
+ * In case the trigger value is out of range of valid blocks, this value my
+ * be arbitrary.
+ */
+ rtems_blkdev_bnum next;
+} rtems_disk_read_ahread;
+
+/**
* @brief Description of a disk device (logical and physical disks).
*
* An array of pointer tables to rtems_disk_device structures is maintained.
@@ -168,6 +200,11 @@ struct rtems_disk_device {
* releases this disk.
*/
bool deleted;
+
+ /**
+ * @brief Read-ahead control for this disk.
+ */
+ rtems_disk_read_ahread read_ahead;
};
/**
diff --git a/cpukit/libblock/src/bdbuf.c b/cpukit/libblock/src/bdbuf.c
index 4c53ff3..424b9a3 100644
--- a/cpukit/libblock/src/bdbuf.c
+++ b/cpukit/libblock/src/bdbuf.c
@@ -134,6 +134,9 @@ typedef struct rtems_bdbuf_cache
size_t group_count; /**< The number of groups. */
rtems_bdbuf_group* groups; /**< The groups. */
+ rtems_id read_ahead_task; /**< Read-ahead task */
+ rtems_chain_control read_ahead_chain; /**< Read-ahead request chain */
+ bool read_ahead_enabled; /**< Read-ahead enabled */
bool initialised; /**< Initialised state. */
} rtems_bdbuf_cache;
@@ -180,6 +183,7 @@ typedef struct rtems_bdbuf_cache
#define RTEMS_BLKDEV_FATAL_BDBUF_STATE_0 RTEMS_BLKDEV_FATAL_ERROR(28)
#define RTEMS_BLKDEV_FATAL_BDBUF_STATE_1 RTEMS_BLKDEV_FATAL_ERROR(29)
#define RTEMS_BLKDEV_FATAL_BDBUF_STATE_2 RTEMS_BLKDEV_FATAL_ERROR(30)
+#define RTEMS_BLKDEV_FATAL_BDBUF_RA_WAKE_UP RTEMS_BLKDEV_FATAL_ERROR(31)
/**
* The events used in this code. These should be system events rather than
@@ -187,6 +191,7 @@ typedef struct rtems_bdbuf_cache
*/
#define RTEMS_BDBUF_TRANSFER_SYNC RTEMS_EVENT_1
#define RTEMS_BDBUF_SWAPOUT_SYNC RTEMS_EVENT_2
+#define RTEMS_BDBUF_READ_AHEAD_WAKE_UP RTEMS_EVENT_1
/**
* Lock semaphore attributes. This is used for locking type mutexes.
@@ -219,11 +224,10 @@ typedef struct rtems_bdbuf_cache
(TOD_MICROSECONDS_TO_TICKS (20000000))
#endif
-/*
- * The swap out task.
- */
static rtems_task rtems_bdbuf_swapout_task(rtems_task_argument arg);
+static rtems_task rtems_bdbuf_read_ahead_task(rtems_task_argument arg);
+
/**
* The Buffer Descriptor cache.
*/
@@ -1365,6 +1369,7 @@ rtems_bdbuf_init (void)
rtems_chain_initialize_empty (&bdbuf_cache.lru);
rtems_chain_initialize_empty (&bdbuf_cache.modified);
rtems_chain_initialize_empty (&bdbuf_cache.sync);
+ rtems_chain_initialize_empty (&bdbuf_cache.read_ahead_chain);
/*
* Create the locks for the cache.
@@ -1486,12 +1491,28 @@ rtems_bdbuf_init (void)
if (sc != RTEMS_SUCCESSFUL)
goto error;
+ if (bdbuf_config.max_read_ahead_blocks > 0)
+ {
+ bdbuf_cache.read_ahead_enabled = true;
+ sc = rtems_bdbuf_create_task (rtems_build_name('B', 'R', 'D', 'A'),
+ bdbuf_config.read_ahead_priority,
+ RTEMS_BDBUF_READ_AHEAD_TASK_PRIORITY_DEFAULT,
+ rtems_bdbuf_read_ahead_task,
+ 0,
+ &bdbuf_cache.read_ahead_task);
+ if (sc != RTEMS_SUCCESSFUL)
+ goto error;
+ }
+
rtems_bdbuf_unlock_cache ();
return RTEMS_SUCCESSFUL;
error:
+ if (bdbuf_cache.read_ahead_task != 0)
+ rtems_task_delete (bdbuf_cache.read_ahead_task);
+
if (bdbuf_cache.swapout != 0)
rtems_task_delete (bdbuf_cache.swapout);
@@ -1852,81 +1873,6 @@ rtems_bdbuf_transfer_done (void* arg, rtems_status_code status)
rtems_event_send (req->io_task, RTEMS_BDBUF_TRANSFER_SYNC);
}
-static void
-rtems_bdbuf_create_read_request (const rtems_disk_device *dd,
- rtems_blkdev_bnum media_block,
- rtems_blkdev_request *req,
- rtems_bdbuf_buffer **bd_ptr)
-{
- rtems_bdbuf_buffer *bd = NULL;
- rtems_blkdev_bnum media_block_end = dd->start + dd->size;
- rtems_blkdev_bnum media_block_count = dd->block_to_media_block_shift >= 0 ?
- 1U << dd->block_to_media_block_shift
- : dd->block_size / dd->media_block_size;
- uint32_t block_size = dd->block_size;
- uint32_t transfer_index = 1;
- uint32_t transfer_count = bdbuf_config.max_read_ahead_blocks + 1;
-
- if (media_block_end - media_block < transfer_count)
- transfer_count = media_block_end - media_block;
-
- req->req = RTEMS_BLKDEV_REQ_READ;
- req->req_done = rtems_bdbuf_transfer_done;
- req->done_arg = req;
- req->io_task = rtems_task_self ();
- req->status = RTEMS_RESOURCE_IN_USE;
- req->bufnum = 0;
-
- bd = rtems_bdbuf_get_buffer_for_access (dd, media_block);
-
- *bd_ptr = bd;
-
- req->bufs [0].user = bd;
- req->bufs [0].block = media_block;
- req->bufs [0].length = block_size;
- req->bufs [0].buffer = bd->buffer;
-
- if (rtems_bdbuf_tracer)
- rtems_bdbuf_show_users ("read", bd);
-
- switch (bd->state)
- {
- case RTEMS_BDBUF_STATE_CACHED:
- case RTEMS_BDBUF_STATE_MODIFIED:
- return;
- case RTEMS_BDBUF_STATE_EMPTY:
- rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_TRANSFER);
- break;
- default:
- rtems_bdbuf_fatal (bd->state, RTEMS_BLKDEV_FATAL_BDBUF_STATE_1);
- break;
- }
-
- while (transfer_index < transfer_count)
- {
- media_block += media_block_count;
-
- bd = rtems_bdbuf_get_buffer_for_read_ahead (dd, media_block);
-
- if (bd == NULL)
- break;
-
- rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_TRANSFER);
-
- req->bufs [transfer_index].user = bd;
- req->bufs [transfer_index].block = media_block;
- req->bufs [transfer_index].length = block_size;
- req->bufs [transfer_index].buffer = bd->buffer;
-
- if (rtems_bdbuf_tracer)
- rtems_bdbuf_show_users ("read-ahead", bd);
-
- ++transfer_index;
- }
-
- req->bufnum = transfer_index;
-}
-
static rtems_status_code
rtems_bdbuf_execute_transfer_request (const rtems_disk_device *dd,
rtems_blkdev_request *req,
@@ -1989,15 +1935,16 @@ rtems_bdbuf_execute_transfer_request (const rtems_disk_device *dd,
return RTEMS_IO_ERROR;
}
-rtems_status_code
-rtems_bdbuf_read (rtems_disk_device *dd,
- rtems_blkdev_bnum block,
- rtems_bdbuf_buffer **bd_ptr)
+static rtems_status_code
+rtems_bdbuf_execute_read_request (const rtems_disk_device *dd,
+ rtems_bdbuf_buffer *bd,
+ uint32_t transfer_count)
{
- rtems_status_code sc = RTEMS_SUCCESSFUL;
rtems_blkdev_request *req = NULL;
- rtems_bdbuf_buffer *bd = NULL;
- rtems_blkdev_bnum media_block;
+ rtems_blkdev_bnum media_block = bd->block;
+ uint32_t media_blocks_per_block = dd->media_blocks_per_block;
+ uint32_t block_size = dd->block_size;
+ uint32_t transfer_index = 1;
/*
* TODO: This type of request structure is wrong and should be removed.
@@ -2005,8 +1952,113 @@ rtems_bdbuf_read (rtems_disk_device *dd,
#define bdbuf_alloc(size) __builtin_alloca (size)
req = bdbuf_alloc (sizeof (rtems_blkdev_request) +
- sizeof (rtems_blkdev_sg_buffer) *
- (bdbuf_config.max_read_ahead_blocks + 1));
+ sizeof (rtems_blkdev_sg_buffer) * transfer_count);
+
+ req->req = RTEMS_BLKDEV_REQ_READ;
+ req->req_done = rtems_bdbuf_transfer_done;
+ req->done_arg = req;
+ req->io_task = rtems_task_self ();
+ req->status = RTEMS_RESOURCE_IN_USE;
+ req->bufnum = 0;
+
+ rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_TRANSFER);
+
+ req->bufs [0].user = bd;
+ req->bufs [0].block = media_block;
+ req->bufs [0].length = block_size;
+ req->bufs [0].buffer = bd->buffer;
+
+ if (rtems_bdbuf_tracer)
+ rtems_bdbuf_show_users ("read", bd);
+
+ while (transfer_index < transfer_count)
+ {
+ media_block += media_blocks_per_block;
+
+ bd = rtems_bdbuf_get_buffer_for_read_ahead (dd, media_block);
+
+ if (bd == NULL)
+ break;
+
+ rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_TRANSFER);
+
+ req->bufs [transfer_index].user = bd;
+ req->bufs [transfer_index].block = media_block;
+ req->bufs [transfer_index].length = block_size;
+ req->bufs [transfer_index].buffer = bd->buffer;
+
+ if (rtems_bdbuf_tracer)
+ rtems_bdbuf_show_users ("read", bd);
+
+ ++transfer_index;
+ }
+
+ req->bufnum = transfer_index;
+
+ return rtems_bdbuf_execute_transfer_request (dd, req, true);
+}
+
+static bool
+rtems_bdbuf_is_read_ahead_active (const rtems_disk_device *dd)
+{
+ return !rtems_chain_is_node_off_chain (&dd->read_ahead.node);
+}
+
+static void
+rtems_bdbuf_read_ahead_cancel (rtems_disk_device *dd)
+{
+ if (rtems_bdbuf_is_read_ahead_active (dd))
+ {
+ rtems_chain_extract_unprotected (&dd->read_ahead.node);
+ rtems_chain_set_off_chain (&dd->read_ahead.node);
+ }
+}
+
+static void
+rtems_bdbuf_read_ahead_reset (rtems_disk_device *dd)
+{
+ rtems_bdbuf_read_ahead_cancel (dd);
+ dd->read_ahead.trigger = RTEMS_DISK_READ_AHEAD_NO_TRIGGER;
+}
+
+static void
+rtems_bdbuf_check_read_ahead_trigger (rtems_disk_device *dd,
+ rtems_blkdev_bnum block)
+{
+ if (dd->read_ahead.trigger == block
+ && !rtems_bdbuf_is_read_ahead_active (dd))
+ {
+ rtems_status_code sc;
+ rtems_chain_control *chain = &bdbuf_cache.read_ahead_chain;
+
+ rtems_chain_append_unprotected (chain, &dd->read_ahead.node);
+ sc = rtems_event_send (bdbuf_cache.read_ahead_task,
+ RTEMS_BDBUF_READ_AHEAD_WAKE_UP);
+ if (sc != RTEMS_SUCCESSFUL)
+ rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_RA_WAKE_UP);
+ }
+}
+
+static void
+rtems_bdbuf_set_read_ahead_trigger (rtems_disk_device *dd,
+ rtems_blkdev_bnum block)
+{
+ if (dd->read_ahead.trigger != block)
+ {
+ rtems_bdbuf_read_ahead_cancel (dd);
+ dd->read_ahead.trigger = block + 1;
+ dd->read_ahead.next = block + 2;
+ }
+}
+
+rtems_status_code
+rtems_bdbuf_read (rtems_disk_device *dd,
+ rtems_blkdev_bnum block,
+ rtems_bdbuf_buffer **bd_ptr)
+{
+ rtems_status_code sc = RTEMS_SUCCESSFUL;
+ rtems_bdbuf_buffer *bd = NULL;
+ rtems_blkdev_bnum media_block;
rtems_bdbuf_lock_cache ();
@@ -2017,42 +2069,33 @@ rtems_bdbuf_read (rtems_disk_device *dd,
printf ("bdbuf:read: %" PRIu32 " (%" PRIu32 ") (dev = %08x)\n",
media_block + dd->start, block, (unsigned) dd->dev);
- rtems_bdbuf_create_read_request (dd, media_block, req, &bd);
-
- if (req->bufnum > 0)
- {
- sc = rtems_bdbuf_execute_transfer_request (dd, req, true);
- if (sc == RTEMS_SUCCESSFUL)
- {
- rtems_chain_extract_unprotected (&bd->link);
- rtems_bdbuf_group_obtain (bd);
- }
- }
-
- if (sc == RTEMS_SUCCESSFUL)
+ rtems_bdbuf_check_read_ahead_trigger (dd, block);
+ bd = rtems_bdbuf_get_buffer_for_access (dd, media_block);
+ switch (bd->state)
{
- switch (bd->state)
- {
- case RTEMS_BDBUF_STATE_CACHED:
+ case RTEMS_BDBUF_STATE_CACHED:
+ rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_ACCESS_CACHED);
+ break;
+ case RTEMS_BDBUF_STATE_MODIFIED:
+ rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_ACCESS_MODIFIED);
+ break;
+ case RTEMS_BDBUF_STATE_EMPTY:
+ rtems_bdbuf_set_read_ahead_trigger (dd, block);
+ sc = rtems_bdbuf_execute_read_request (dd, bd, 1);
+ if (sc == RTEMS_SUCCESSFUL)
+ {
rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_ACCESS_CACHED);
- break;
- case RTEMS_BDBUF_STATE_MODIFIED:
- rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_ACCESS_MODIFIED);
- break;
- default:
- rtems_bdbuf_fatal (bd->state, RTEMS_BLKDEV_FATAL_BDBUF_STATE_4);
- break;
- }
-
- if (rtems_bdbuf_tracer)
- {
- rtems_bdbuf_show_users ("read", bd);
- rtems_bdbuf_show_usage ();
- }
- }
- else
- {
- bd = NULL;
+ rtems_chain_extract_unprotected (&bd->link);
+ rtems_bdbuf_group_obtain (bd);
+ }
+ else
+ {
+ bd = NULL;
+ }
+ break;
+ default:
+ rtems_bdbuf_fatal (bd->state, RTEMS_BLKDEV_FATAL_BDBUF_STATE_4);
+ break;
}
}
@@ -2884,6 +2927,7 @@ rtems_bdbuf_purge_dev (rtems_disk_device *dd)
rtems_chain_initialize_empty (&purge_list);
rtems_bdbuf_lock_cache ();
+ rtems_bdbuf_read_ahead_reset (dd);
rtems_bdbuf_gather_for_purge (&purge_list, dd);
rtems_bdbuf_purge_list (&purge_list);
rtems_bdbuf_unlock_cache ();
@@ -2919,6 +2963,8 @@ rtems_bdbuf_set_block_size (rtems_disk_device *dd, uint32_t block_size)
dd->media_blocks_per_block = media_blocks_per_block;
dd->block_to_media_block_shift = block_to_media_block_shift;
dd->bds_per_group = bds_per_group;
+
+ rtems_bdbuf_read_ahead_reset (dd);
}
else
{
@@ -2934,3 +2980,62 @@ rtems_bdbuf_set_block_size (rtems_disk_device *dd, uint32_t block_size)
return sc;
}
+
+static rtems_task
+rtems_bdbuf_read_ahead_task (rtems_task_argument arg)
+{
+ rtems_chain_control *chain = &bdbuf_cache.read_ahead_chain;
+
+ while (bdbuf_cache.read_ahead_enabled)
+ {
+ rtems_chain_node *node;
+
+ rtems_bdbuf_wait_for_event (RTEMS_BDBUF_READ_AHEAD_WAKE_UP);
+ rtems_bdbuf_lock_cache ();
+
+ while ((node = rtems_chain_get_unprotected (chain)) != NULL)
+ {
+ rtems_disk_device *dd = (rtems_disk_device *)
+ ((char *) node - offsetof (rtems_disk_device, read_ahead.node));
+ rtems_blkdev_bnum block = dd->read_ahead.next;
+ rtems_blkdev_bnum media_block = 0;
+ rtems_status_code sc =
+ rtems_bdbuf_get_media_block (dd, block, &media_block);
+
+ rtems_chain_set_off_chain (&dd->read_ahead.node);
+
+ if (sc == RTEMS_SUCCESSFUL)
+ {
+ rtems_bdbuf_buffer *bd =
+ rtems_bdbuf_get_buffer_for_read_ahead (dd, media_block);
+
+ if (bd != NULL)
+ {
+ uint32_t transfer_count = dd->block_count - block;
+ uint32_t max_transfer_count = bdbuf_config.max_read_ahead_blocks;
+
+ if (transfer_count >= max_transfer_count)
+ {
+ transfer_count = max_transfer_count;
+ dd->read_ahead.trigger += max_transfer_count / 2 + 1;
+ dd->read_ahead.next += max_transfer_count;
+ }
+ else
+ {
+ dd->read_ahead.trigger = RTEMS_DISK_READ_AHEAD_NO_TRIGGER;
+ }
+
+ rtems_bdbuf_execute_read_request (dd, bd, transfer_count);
+ }
+ }
+ else
+ {
+ dd->read_ahead.trigger = RTEMS_DISK_READ_AHEAD_NO_TRIGGER;
+ }
+ }
+
+ rtems_bdbuf_unlock_cache ();
+ }
+
+ rtems_task_delete (RTEMS_SELF);
+}
diff --git a/cpukit/libblock/src/diskdevs-init.c b/cpukit/libblock/src/diskdevs-init.c
index ccf954a..5ec96b2 100644
--- a/cpukit/libblock/src/diskdevs-init.c
+++ b/cpukit/libblock/src/diskdevs-init.c
@@ -36,6 +36,7 @@ rtems_status_code rtems_disk_init_phys(
dd->media_block_size = block_size;
dd->ioctl = handler;
dd->driver_data = driver_data;
+ dd->read_ahead.trigger = RTEMS_DISK_READ_AHEAD_NO_TRIGGER;
if (block_count > 0) {
if ((*handler)(dd, RTEMS_BLKIO_CAPABILITIES, &dd->capabilities) != 0) {
@@ -67,6 +68,7 @@ rtems_status_code rtems_disk_init_log(
dd->media_block_size = phys_dd->media_block_size;
dd->ioctl = phys_dd->ioctl;
dd->driver_data = phys_dd->driver_data;
+ dd->read_ahead.trigger = RTEMS_DISK_READ_AHEAD_NO_TRIGGER;
if (phys_dd->phys_dev == phys_dd) {
rtems_blkdev_bnum phys_block_count = phys_dd->size;
diff --git a/cpukit/sapi/include/confdefs.h b/cpukit/sapi/include/confdefs.h
index 4e43a27..0f804ee 100644
--- a/cpukit/sapi/include/confdefs.h
+++ b/cpukit/sapi/include/confdefs.h
@@ -1241,6 +1241,10 @@ rtems_fs_init_functions_t rtems_fs_init_helper =
#define CONFIGURE_BDBUF_BUFFER_MAX_SIZE \
RTEMS_BDBUF_BUFFER_MAX_SIZE_DEFAULT
#endif
+ #ifndef CONFIGURE_BDBUF_READ_AHEAD_TASK_PRIORITY
+ #define CONFIGURE_BDBUF_READ_AHEAD_TASK_PRIORITY \
+ RTEMS_BDBUF_READ_AHEAD_TASK_PRIORITY_DEFAULT
+ #endif
#ifdef CONFIGURE_INIT
const rtems_bdbuf_config rtems_bdbuf_configuration = {
CONFIGURE_BDBUF_MAX_READ_AHEAD_BLOCKS,
@@ -1253,11 +1257,14 @@ rtems_fs_init_functions_t rtems_fs_init_helper =
CONFIGURE_BDBUF_TASK_STACK_SIZE,
CONFIGURE_BDBUF_CACHE_MEMORY_SIZE,
CONFIGURE_BDBUF_BUFFER_MIN_SIZE,
- CONFIGURE_BDBUF_BUFFER_MAX_SIZE
+ CONFIGURE_BDBUF_BUFFER_MAX_SIZE,
+ CONFIGURE_BDBUF_READ_AHEAD_TASK_PRIORITY
};
#endif
- #define CONFIGURE_LIBBLOCK_TASKS (1 + CONFIGURE_SWAPOUT_WORKER_TASKS)
+ #define CONFIGURE_LIBBLOCK_TASKS \
+ (1 + CONFIGURE_SWAPOUT_WORKER_TASKS + \
+ (CONFIGURE_BDBUF_MAX_READ_AHEAD_BLOCKS != 0))
#define CONFIGURE_LIBBLOCK_TASK_EXTRA_STACKS \
(CONFIGURE_LIBBLOCK_TASKS * \
diff --git a/testsuites/libtests/Makefile.am b/testsuites/libtests/Makefile.am
index 1274f26..9747ad1 100644
--- a/testsuites/libtests/Makefile.am
+++ b/testsuites/libtests/Makefile.am
@@ -1,6 +1,7 @@
ACLOCAL_AMFLAGS = -I ../aclocal
SUBDIRS = POSIX
+SUBDIRS += block13
SUBDIRS += rbheap01
SUBDIRS += flashdisk01
diff --git a/testsuites/libtests/block13/Makefile.am b/testsuites/libtests/block13/Makefile.am
new file mode 100644
index 0000000..9b4a76d
--- /dev/null
+++ b/testsuites/libtests/block13/Makefile.am
@@ -0,0 +1,19 @@
+rtems_tests_PROGRAMS = block13
+block13_SOURCES = init.c
+
+dist_rtems_tests_DATA = block13.scn block13.doc
+
+include $(RTEMS_ROOT)/make/custom/@RTEMS_BSP at .cfg
+include $(top_srcdir)/../automake/compile.am
+include $(top_srcdir)/../automake/leaf.am
+
+AM_CPPFLAGS += -I$(top_srcdir)/../support/include
+
+LINK_OBJS = $(block13_OBJECTS)
+LINK_LIBS = $(block13_LDLIBS)
+
+block13$(EXEEXT): $(block13_OBJECTS) $(block13_DEPENDENCIES)
+ @rm -f block13$(EXEEXT)
+ $(make-exe)
+
+include $(top_srcdir)/../automake/local.am
diff --git a/testsuites/libtests/block13/block13.doc b/testsuites/libtests/block13/block13.doc
new file mode 100644
index 0000000..04fc066
--- /dev/null
+++ b/testsuites/libtests/block13/block13.doc
@@ -0,0 +1,11 @@
+This file describes the directives and concepts tested by this test set.
+
+test set name: block13
+
+directives:
+
+ TBD
+
+concepts:
+
+ Tests the read-ahead feature of bdbuf.
diff --git a/testsuites/libtests/block13/block13.scn b/testsuites/libtests/block13/block13.scn
new file mode 100644
index 0000000..8cce718
--- /dev/null
+++ b/testsuites/libtests/block13/block13.scn
@@ -0,0 +1,11 @@
+*** TEST BLOCK 13 ***
+0 2 3 4 5 6 7 8
+reset
+8
+reset
+7
+reset
+6 7
+reset
+5 6 8
+*** END OF TEST BLOCK 13 ***
diff --git a/testsuites/libtests/block13/init.c b/testsuites/libtests/block13/init.c
new file mode 100644
index 0000000..43ce388
--- /dev/null
+++ b/testsuites/libtests/block13/init.c
@@ -0,0 +1,232 @@
+/*
+ * Copyright (c) 2012 embedded brains GmbH. All rights reserved.
+ *
+ * embedded brains GmbH
+ * Obere Lagerstr. 30
+ * 82178 Puchheim
+ * Germany
+ * <rtems at 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+ #include "config.h"
+#endif
+
+#include "tmacros.h"
+
+#include <errno.h>
+#include <string.h>
+
+#include <rtems/blkdev.h>
+#include <rtems/bdbuf.h>
+
+#define BLOCK_COUNT 9
+#define READ_COUNT 19
+
+static int block_access_counts [BLOCK_COUNT];
+
+#define RESET_CACHE (-1)
+
+static const int action_sequence [READ_COUNT] = {
+ 0, 2, 3, 4, 5, 6, 7, 8,
+ RESET_CACHE,
+ 8,
+ RESET_CACHE,
+ 7,
+ RESET_CACHE,
+ 6, 7,
+ RESET_CACHE,
+ 5, 6, 8
+};
+
+#define UNUSED_LINE { 0, 0, 0, 0, 0, 0, 0, 0, 0 }
+
+static int expected_block_access_counts [READ_COUNT] [BLOCK_COUNT] = {
+ { 1, 0, 0, 0, 0, 0, 0, 0, 0 },
+ { 1, 0, 1, 0, 0, 0, 0, 0, 0 },
+ { 1, 0, 1, 1, 1, 1, 0, 0, 0 },
+ { 1, 0, 1, 1, 1, 1, 0, 0, 0 },
+ { 1, 0, 1, 1, 1, 1, 1, 1, 0 },
+ { 1, 0, 1, 1, 1, 1, 1, 1, 0 },
+ { 1, 0, 1, 1, 1, 1, 1, 1, 1 },
+ { 1, 0, 1, 1, 1, 1, 1, 1, 1 },
+ UNUSED_LINE,
+ { 0, 0, 0, 0, 0, 0, 0, 0, 1 },
+ UNUSED_LINE,
+ { 0, 0, 0, 0, 0, 0, 0, 1, 0 },
+ UNUSED_LINE,
+ { 0, 0, 0, 0, 0, 0, 1, 0, 0 },
+ { 0, 0, 0, 0, 0, 0, 1, 1, 1 },
+ UNUSED_LINE,
+ { 0, 0, 0, 0, 0, 1, 0, 0, 0 },
+ { 0, 0, 0, 0, 0, 1, 1, 1, 1 },
+ { 0, 0, 0, 0, 0, 1, 1, 1, 1 }
+};
+
+#define NO_TRIGGER RTEMS_DISK_READ_AHEAD_NO_TRIGGER
+
+#define TRIGGER_AFTER_RESET RTEMS_DISK_READ_AHEAD_NO_TRIGGER
+
+static const rtems_blkdev_bnum trigger [READ_COUNT] = {
+ 1, 3, 5, 5, 7, 7, NO_TRIGGER, NO_TRIGGER,
+ TRIGGER_AFTER_RESET,
+ 9,
+ TRIGGER_AFTER_RESET,
+ 8,
+ TRIGGER_AFTER_RESET,
+ 7, NO_TRIGGER,
+ TRIGGER_AFTER_RESET,
+ 6, 8, NO_TRIGGER
+};
+
+#define NOT_CHANGED_BY_RESET(i) (i)
+
+static const rtems_blkdev_bnum next [READ_COUNT] = {
+ 2, 4, 6, 6, 8, 8, 8, 8,
+ NOT_CHANGED_BY_RESET(8),
+ 10,
+ NOT_CHANGED_BY_RESET(10),
+ 9,
+ NOT_CHANGED_BY_RESET(9),
+ 8, 8,
+ NOT_CHANGED_BY_RESET(8),
+ 7, 9, 9
+};
+
+static int test_disk_ioctl(rtems_disk_device *dd, uint32_t req, void *arg)
+{
+ int rv = 0;
+
+ if (req == RTEMS_BLKIO_REQUEST) {
+ rtems_blkdev_request *breq = arg;
+ rtems_blkdev_sg_buffer *sg = breq->bufs;
+ uint32_t i;
+
+ rtems_test_assert(breq->req == RTEMS_BLKDEV_REQ_READ);
+
+ for (i = 0; i < breq->bufnum; ++i) {
+ rtems_blkdev_bnum block = sg [i].block;
+
+ rtems_test_assert(block < BLOCK_COUNT);
+
+ ++block_access_counts [block];
+ }
+
+ (*breq->req_done)(breq->done_arg, RTEMS_SUCCESSFUL);
+ } else {
+ errno = EINVAL;
+ rv = -1;
+ }
+
+ return rv;
+}
+
+static void test_read_ahead(rtems_disk_device *dd)
+{
+ int i;
+
+ for (i = 0; i < READ_COUNT; ++i) {
+ int action = action_sequence [i];
+
+ if (action != RESET_CACHE) {
+ rtems_blkdev_bnum block = (rtems_blkdev_bnum) action;
+ rtems_status_code sc;
+ rtems_bdbuf_buffer *bd;
+
+ printf("%i ", action);
+
+ sc = rtems_bdbuf_read(dd, block, &bd);
+ rtems_test_assert(sc == RTEMS_SUCCESSFUL);
+
+ sc = rtems_bdbuf_release(bd);
+ rtems_test_assert(sc == RTEMS_SUCCESSFUL);
+
+ rtems_test_assert(
+ memcmp(
+ block_access_counts,
+ expected_block_access_counts [i],
+ sizeof(block_access_counts)
+ ) == 0
+ );
+ } else {
+ printf("\nreset\n");
+
+ rtems_bdbuf_purge_dev(dd);
+ memset(&block_access_counts, 0, sizeof(block_access_counts));
+ }
+
+ rtems_test_assert(trigger [i] == dd->read_ahead.trigger);
+ rtems_test_assert(next [i] == dd->read_ahead.next);
+ }
+
+ printf("\n");
+}
+
+static void test(void)
+{
+ rtems_status_code sc;
+ dev_t dev = 0;
+ rtems_disk_device *dd;
+
+ sc = rtems_disk_io_initialize();
+ rtems_test_assert(sc == RTEMS_SUCCESSFUL);
+
+ sc = rtems_disk_create_phys(
+ dev,
+ 1,
+ BLOCK_COUNT,
+ test_disk_ioctl,
+ NULL,
+ NULL
+ );
+ rtems_test_assert(sc == RTEMS_SUCCESSFUL);
+
+ dd = rtems_disk_obtain(dev);
+ rtems_test_assert(dd != NULL);
+
+ test_read_ahead(dd);
+
+ sc = rtems_disk_release(dd);
+ rtems_test_assert(sc == RTEMS_SUCCESSFUL);
+
+ sc = rtems_disk_delete(dev);
+ rtems_test_assert(sc == RTEMS_SUCCESSFUL);
+}
+
+static void Init(rtems_task_argument arg)
+{
+ puts("\n\n*** TEST BLOCK 13 ***");
+
+ test();
+
+ puts("*** END OF TEST BLOCK 13 ***");
+
+ rtems_test_exit(0);
+}
+
+#define CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER
+#define CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER
+#define CONFIGURE_APPLICATION_NEEDS_LIBBLOCK
+
+#define CONFIGURE_BDBUF_BUFFER_MIN_SIZE 1
+#define CONFIGURE_BDBUF_BUFFER_MAX_SIZE 1
+#define CONFIGURE_BDBUF_CACHE_MEMORY_SIZE BLOCK_COUNT
+#define CONFIGURE_BDBUF_MAX_READ_AHEAD_BLOCKS 2
+#define CONFIGURE_BDBUF_READ_AHEAD_TASK_PRIORITY 1
+
+#define CONFIGURE_USE_IMFS_AS_BASE_FILESYSTEM
+
+#define CONFIGURE_MAXIMUM_TASKS 1
+
+#define CONFIGURE_RTEMS_INIT_TASKS_TABLE
+
+#define CONFIGURE_INIT_TASK_INITIAL_MODES RTEMS_DEFAULT_MODES
+#define CONFIGURE_INIT_TASK_PRIORITY 2
+
+#define CONFIGURE_INIT
+
+#include <rtems/confdefs.h>
diff --git a/testsuites/libtests/configure.ac b/testsuites/libtests/configure.ac
index f6af3b1..7df0520 100644
--- a/testsuites/libtests/configure.ac
+++ b/testsuites/libtests/configure.ac
@@ -41,6 +41,7 @@ AM_CONDITIONAL(NETTESTS,test "$rtems_cv_RTEMS_NETWORKING" = "yes")
# Explicitly list all Makefiles here
AC_CONFIG_FILES([Makefile
+block13/Makefile
rbheap01/Makefile
syscall01/Makefile
flashdisk01/Makefile
More information about the vc
mailing list