Changeset dba4a23 in mainline for uspace/srv/fs/fat/fat.h

Timestamp:

2010-07-28T15:22:22Z (14 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

4637c72, 9a1d8ab

Parents:

6da81e0

Message:

Speed up sequential I/O by caching the "current" cluster in fat_block_get().
This improves sequentil read of a 5m file (using the cat command) by 45 seconds
(73s → 28s).

File:

• uspace/srv/fs/fat/fat.h (modified) (1 diff)

uspace/srv/fs/fat/fat.h

@@ -213 +213 @@
 
         /*
-         * Cache of the node's last cluster to avoid some unnecessary FAT walks.
+         * Cache of the node's last and "current" cluster to avoid some
+         * unnecessary FAT walks.
          */
-        bool                    lastc_cached_valid;
-        fat_cluster_t           lastc_cached_value;
+        /* Node's last cluster in FAT. */
+        bool            lastc_cached_valid;
+        fat_cluster_t   lastc_cached_value;
+        /* Node's "current" cluster, i.e. where the last I/O took place. */
+        bool            currc_cached_valid;
+        aoff64_t        currc_cached_bn;
+        fat_cluster_t   currc_cached_value;
 } fat_node_t;