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authorJosef Bacik <jbacik@fusionio.com>2012-09-25 14:25:58 -0400
committerChris Mason <chris.mason@fusionio.com>2012-10-09 09:15:40 -0400
commitde0022b9da616b95ea5b41eab32da825b0b5150f (patch)
tree5a96323c250b846da82da82ed999828255be0e34 /fs/btrfs/disk-io.c
parent221b831835421f9451182611fa25fa60f440662f (diff)
Btrfs: do not async metadata csumming in certain situations
There are a coule scenarios where farming metadata csumming off to an async thread doesn't help. The first is if our processor supports crc32c, in which case the csumming will be fast and so the overhead of the async model is not worth the cost. The other case is for our tree log. We will be making that stuff dirty and writing it out and waiting for it immediately. Even with software crc32c this gives me a ~15% increase in speed with O_SYNC workloads. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Diffstat (limited to 'fs/btrfs/disk-io.c')
-rw-r--r--fs/btrfs/disk-io.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index dcaf55695e6f..aa02eab8c40b 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -46,6 +46,10 @@
#include "check-integrity.h"
#include "rcu-string.h"
+#ifdef CONFIG_X86
+#include <asm/cpufeature.h>
+#endif
+
static struct extent_io_ops btree_extent_io_ops;
static void end_workqueue_fn(struct btrfs_work *work);
static void free_fs_root(struct btrfs_root *root);
@@ -859,10 +863,22 @@ static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
}
+static int check_async_write(struct inode *inode, unsigned long bio_flags)
+{
+ if (bio_flags & EXTENT_BIO_TREE_LOG)
+ return 0;
+#ifdef CONFIG_X86
+ if (cpu_has_xmm4_2)
+ return 0;
+#endif
+ return 1;
+}
+
static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
int mirror_num, unsigned long bio_flags,
u64 bio_offset)
{
+ int async = check_async_write(inode, bio_flags);
int ret;
if (!(rw & REQ_WRITE)) {
@@ -877,6 +893,12 @@ static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
return ret;
return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
mirror_num, 0);
+ } else if (!async) {
+ ret = btree_csum_one_bio(bio);
+ if (ret)
+ return ret;
+ return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
+ mirror_num, 0);
}
/*