Filipe David Borba Manana d7396f0735 Btrfs: optimize key searches in btrfs_search_slot ... When the binary search returns 0 (exact match), the target key will necessarily be at slot 0 of all nodes below the current one, so in this case the binary search is not needed because it will always return 0, and we waste time doing it, holding node locks for longer than necessary, etc. Below follow histograms with the times spent on the current approach of doing a binary search when the previous binary search returned 0, and times for the new approach, which directly picks the first item/child node in the leaf/node. Current approach: Count: 6682 Range: 35.000 - 8370.000; Mean: 85.837; Median: 75.000; Stddev: 106.429 Percentiles: 90th: 124.000; 95th: 145.000; 99th: 206.000 35.000 - 61.080: 1235 ################ 61.080 - 106.053: 4207 ##################################################### 106.053 - 183.606: 1122 ############## 183.606 - 317.341: 111 # 317.341 - 547.959: 6 | 547.959 - 8370.000: 1 | Approach proposed by this patch: Count: 6682 Range: 6.000 - 135.000; Mean: 16.690; Median: 16.000; Stddev: 7.160 Percentiles: 90th: 23.000; 95th: 27.000; 99th: 40.000 6.000 - 8.418: 58 # 8.418 - 11.670: 1149 ######################### 11.670 - 16.046: 2418 ##################################################### 16.046 - 21.934: 2098 ############################################## 21.934 - 29.854: 744 ################ 29.854 - 40.511: 154 ### 40.511 - 54.848: 41 # 54.848 - 74.136: 5 | 74.136 - 100.087: 9 | 100.087 - 135.000: 6 | These samples were captured during a run of the btrfs tests 001, 002 and 004 in the xfstests, with a leaf/node size of 4Kb. Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>		2013-09-01 08:16:42 -04:00
..
tests	Btrfs: separate out tests into their own directory	2013-09-01 08:15:38 -04:00
acl.c
async-thread.c
async-thread.h
backref.c	Btrfs: allocate prelim_ref with a slab allocater	2013-09-01 08:16:27 -04:00
backref.h	Btrfs: allocate prelim_ref with a slab allocater	2013-09-01 08:16:27 -04:00
btrfs_inode.h	Btrfs: don't cache the csum value into the extent state tree	2013-09-01 08:04:33 -04:00
check-integrity.c	Btrfs: Use %z to format size_t	2013-09-01 08:16:19 -04:00
check-integrity.h
compat.h
compression.c	Btrfs: Remove superfluous casts from u64 to unsigned long long	2013-09-01 08:16:08 -04:00
compression.h
ctree.c	Btrfs: optimize key searches in btrfs_search_slot	2013-09-01 08:16:42 -04:00
ctree.h	Btrfs: fix memory leak of uuid_root in free_fs_info	2013-09-01 08:16:37 -04:00
delayed-inode.c	Btrfs: fix printing of non NULL terminated string	2013-09-01 08:16:20 -04:00
delayed-inode.h
delayed-ref.c	Btrfs: get rid of sparse warnings	2013-09-01 08:15:50 -04:00
delayed-ref.h
dev-replace.c	Btrfs: Make BTRFS_DEV_REPLACE_DEVID an unsigned long long constant	2013-09-01 08:16:09 -04:00
dev-replace.h
dir-item.c
disk-io.c	Btrfs: don't use an async starter for most of our workers	2013-09-01 08:16:41 -04:00
disk-io.h
export.c
export.h
extent_io.c	Btrfs: PAGE_CACHE_SIZE is already unsigned long	2013-09-01 08:16:17 -04:00
extent_io.h	btrfs: mark some local function as 'static'	2013-09-01 08:15:51 -04:00
extent_map.c
extent_map.h
extent-tree.c	Btrfs: remove ourselves from the cluster list under lock	2013-09-01 08:16:23 -04:00
file-item.c	Btrfs: Remove superfluous casts from u64 to unsigned long long	2013-09-01 08:16:08 -04:00
file.c	Btrf: cleanup: don't check for root_refs == 0 twice	2013-09-01 08:16:29 -04:00
free-space-cache.c	Btrfs: convert all bug_ons in free-space-cache.c	2013-09-01 08:16:33 -04:00
free-space-cache.h	Btrfs: separate out tests into their own directory	2013-09-01 08:15:38 -04:00
hash.h
inode-item.c
inode-map.c
inode-map.h
inode.c	Btrfs: only update disk_i_size as we remove extents	2013-09-01 08:16:40 -04:00
ioctl.c	btrfs: return btrfs error code for dev excl ops err	2013-09-01 08:16:35 -04:00
Kconfig	Btrfs: add support for asserts	2013-09-01 08:16:32 -04:00
locking.c
locking.h
lzo.c	Btrfs: return -1 when lzo compression makes data bigger	2013-09-01 07:57:19 -04:00
Makefile	Btrfs: introduce a tree for items that map UUIDs to something	2013-09-01 08:15:52 -04:00
math.h
ordered-data.c	Btrfs: allow partial ordered extent completion	2013-09-01 08:16:34 -04:00
ordered-data.h	Btrfs: allow partial ordered extent completion	2013-09-01 08:16:34 -04:00
orphan.c
print-tree.c	Btrfs: Remove superfluous casts from u64 to unsigned long long	2013-09-01 08:16:08 -04:00
print-tree.h
qgroup.c	Btrfs: Remove superfluous casts from u64 to unsigned long long	2013-09-01 08:16:08 -04:00
raid56.c	Btrfs, raid56: fix memory leak when allocating pages for p/q stripes failed	2013-09-01 08:04:27 -04:00
raid56.h
rcu-string.h
reada.c
relocation.c	Btrf: cleanup: don't check for root_refs == 0 twice	2013-09-01 08:16:29 -04:00
root-tree.c	Btrfs: Remove superfluous casts from u64 to unsigned long long	2013-09-01 08:16:08 -04:00
scrub.c	Btrf: cleanup: don't check for root_refs == 0 twice	2013-09-01 08:16:29 -04:00
send.c	btrfs: reuse kbasename helper	2013-09-01 08:16:36 -04:00
send.h
struct-funcs.c
super.c	Btrfs: allocate prelim_ref with a slab allocater	2013-09-01 08:16:27 -04:00
sysfs.c
transaction.c	Btrfs: Remove superfluous casts from u64 to unsigned long long	2013-09-01 08:16:08 -04:00
transaction.h	btrfs: mark some local function as 'static'	2013-09-01 08:15:51 -04:00
tree-defrag.c
tree-log.c	Btrfs: don't ignore errors from btrfs_run_delayed_items	2013-09-01 08:04:54 -04:00
tree-log.h
ulist.c	Btrfs: fix crash regarding to ulist_add_merge	2013-07-02 11:50:59 -04:00
ulist.h
uuid-tree.c	Btrfs: check UUID tree during mount if required	2013-09-01 08:15:58 -04:00
volumes.c	Btrfs: fix deadlock in uuid scan kthread	2013-09-01 08:16:39 -04:00
volumes.h	Btrfs: add btrfs_alloc_device and switch to it	2013-09-01 08:16:04 -04:00
xattr.c
xattr.h
zlib.c