sysmo-bts
/
barebox
9
0
Fork 0
Code Releases Activity

ramfs: rember last accessed chunk 

Writing big files takes longer and longer because of the chunk list
By storing a pointer of the recent used chunk in the inode, access times are
improved.
Testet on with tftp 10M:
OMAP4 chunk size 4096: 12244ms 8192: 4239ms
	patched        2647ms        2785ms
i.MX35 chunk size 8192: 7225ms
	patched		2691ms

No impact on much smaller files seen

Signed-off-by: Jan Weitzel <j.weitzel@phytec.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Jan Weitzel 2012-05-16 08:10:16 +02:00 committed by Sascha Hauer
parent 3f66e8dc57
commit 011801d22c
1 changed files with 37 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

47
fs/ramfs.c
View File

@ -48,6 +48,10 @@ struct ramfs_inode {
ulong size;
struct ramfs_chunk *data;
/* Points to recently used chunk */
int recent_chunk;
struct ramfs_chunk *recent_chunkp;
};
struct ramfs_priv {
@ -297,6 +301,35 @@ static int ramfs_close(struct device_d *dev, FILE *f)
return 0;
}
static struct ramfs_chunk *ramfs_find_chunk(struct ramfs_inode *node, int chunk)
{
struct ramfs_chunk *data;
int left = chunk;
if (chunk == 0)
return node->data;
if (node->recent_chunk == chunk)
return node->recent_chunkp;
if (node->recent_chunk < chunk && node->recent_chunk != 0) {
/* Start at last known chunk */
data = node->recent_chunkp;
left -= node->recent_chunk;
} else {
/* Start at first chunk */
data = node->data;
}
while (left--)
data = data->next;
node->recent_chunkp = data;
node->recent_chunk = chunk;
return data;
}
static int ramfs_read(struct device_d *_dev, FILE *f, void *buf, size_t insize)
{
struct ramfs_inode *node = (struct ramfs_inode *)f->inode;
@ -311,11 +344,7 @@ static int ramfs_read(struct device_d *_dev, FILE *f, void *buf, size_t insize)
debug("%s: reading from chunk %d\n", __FUNCTION__, chunk);
/* Position ourself in stream */
data = node->data;
while (chunk) {
data = data->next;
chunk--;
}
data = ramfs_find_chunk(node, chunk);
ofs = f->pos % CHUNK_SIZE;
/* Read till end of current chunk */
@ -364,11 +393,7 @@ static int ramfs_write(struct device_d *_dev, FILE *f, const void *buf, size_t i
debug("%s: writing to chunk %d\n", __FUNCTION__, chunk);
/* Position ourself in stream */
data = node->data;
while (chunk) {
data = data->next;
chunk--;
}
data = ramfs_find_chunk(node, chunk);
ofs = f->pos % CHUNK_SIZE;
/* Write till end of current chunk */
@ -429,6 +454,8 @@ static int ramfs_truncate(struct device_d *dev, FILE *f, ulong size)
ramfs_put_chunk(data);
data = tmp;
}
if (node->recent_chunk > newchunks)
node->recent_chunk = 0;
}
if (newchunks > oldchunks) {