linux/fs/btrfs
Miao Xie fa7c14947a Btrfs: improve jitter performance of the sequential buffered write
The performance was slowed down sometimes when we ran sysbench to measure
the performance of the sequential buffered write by 2 or more threads.

It was because the write order of the test threads might be confused
by the task scheduler, and the coming write would be beyond the end of
the file, in this case, we need insert dummy file extents and create
a hole for the area we skip. But in order to avoid the ongoing ordered
extents which are in the area, we need wait for them. Unfortunately,
the current code doesn't check if there are ordered extents in the area
or not, try to find and flush the dirty pages directly, but in fact,
there is no dirty page in that area, this step of the current code is
unnecessary, and just wastes time. Sometimes, it would increase
the contention of some locks, and makes the performance slow down suddenly.

So we remove the ordered extent flush function before the check, and flush
the dirty pages and wait for the ordered extents only when we find them.

According to my test, we got 1-2 times of the performance regression when
we ran the test by 10 times before applying this patch. After applying
this patch, the regression went away.

Test Environment:
 CPU:		1CPU * 4Cores
 Memory:	6GB
 Partition:	20GB

Test Command:
 # sysbench --test=fileio --file-total-size=16G --file-test-mode=seqwr \
 > --num-threads=512 --file-block-size=16384 --max-time=60 --max-requests=0 run

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-11-11 21:54:38 -05:00
..
tests Btrfs: add a sanity test for btrfs_split_item 2013-11-11 21:51:02 -05:00
acl.c Btrfs: skip adding an acl attribute if we don't have to 2012-12-16 20:46:15 -05:00
async-thread.c Btrfs: eliminate races in worker stopping code 2013-10-04 16:02:13 -04:00
async-thread.h Btrfs: eliminate races in worker stopping code 2013-10-04 16:02:13 -04:00
backref.c btrfs: drop unused parameter from btrfs_item_nr 2013-11-11 21:50:48 -05:00
backref.h Btrfs: allocate prelim_ref with a slab allocater 2013-09-01 08:16:27 -04:00
btrfs_inode.h Btrfs: check roots last log commit when checking if an inode has been logged 2013-09-21 11:05:24 -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 btrfs: make static code static & remove dead code 2013-05-06 15:55:23 -04:00
ctree.c btrfs: remove unused parameter from btrfs_header_fsid 2013-11-11 21:54:16 -05:00
ctree.h btrfs: remove unused parameter from btrfs_header_fsid 2013-11-11 21:54:16 -05:00
delayed-inode.c Btrfs: fix printing of non NULL terminated string 2013-09-01 08:16:20 -04:00
delayed-inode.h [readdir] convert btrfs 2013-06-29 12:57:00 +04:00
delayed-ref.c Btrfs: get rid of sparse warnings 2013-09-01 08:15:50 -04:00
delayed-ref.h Btrfs: handle running extent ops with skinny metadata 2013-05-17 21:40:15 -04:00
dev-replace.c Merge branch 'for-linus' into for-linus-3.12 2013-10-05 10:51:32 -04:00
dev-replace.h Btrfs: add new sources for device replace code 2012-12-12 17:15:41 -05:00
dir-item.c btrfs: drop unused parameter from btrfs_item_nr 2013-11-11 21:50:48 -05:00
disk-io.c btrfs: remove unused parameter from btrfs_header_fsid 2013-11-11 21:54:16 -05:00
disk-io.h Btrfs: add a sanity test for btrfs_split_item 2013-11-11 21:51:02 -05:00
export.c Btrfs: cleanup: don't check the same thing twice 2013-06-14 11:29:30 -04:00
export.h
extent_io.c Btrfs: export btrfs space shared info to userspace 2013-11-11 21:52:54 -05:00
extent_io.h btrfs: mark some local function as 'static' 2013-09-01 08:15:51 -04:00
extent_map.c btrfs: make static code static & remove dead code 2013-05-06 15:55:23 -04:00
extent_map.h Btrfs: fix bad extent logging 2013-05-06 15:54:34 -04:00
extent-tree.c Btrfs: don't leak block group on error 2013-11-11 21:53:15 -05:00
file-item.c Btrfs: Remove superfluous casts from u64 to unsigned long long 2013-09-01 08:16:08 -04:00
file.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2013-09-22 14:58:49 -07:00
free-space-cache.c Btrfs: remove path arg from btrfs_truncate_free_space_cache 2013-11-11 21:51:33 -05:00
free-space-cache.h Btrfs: remove path arg from btrfs_truncate_free_space_cache 2013-11-11 21:51:33 -05:00
hash.h btrfs: extended inode refs 2012-10-09 09:14:45 -04:00
inode-item.c btrfs: drop unused parameter from btrfs_item_nr 2013-11-11 21:50:48 -05:00
inode-map.c Btrfs: remove path arg from btrfs_truncate_free_space_cache 2013-11-11 21:51:33 -05:00
inode-map.h
inode.c Btrfs: improve jitter performance of the sequential buffered write 2013-11-11 21:54:38 -05:00
ioctl.c btrfs: remove unused parameter from btrfs_header_fsid 2013-11-11 21:54:16 -05:00
Kconfig Btrfs: add support for asserts 2013-09-01 08:16:32 -04:00
locking.c btrfs: make static code static & remove dead code 2013-05-06 15:55:23 -04:00
locking.h Btrfs: remove btrfs_try_spin_lock 2013-03-14 14:57:10 -04:00
lzo.c Btrfs: return -1 when lzo compression makes data bigger 2013-09-01 07:57:19 -04:00
Makefile Btrfs: add a sanity test for btrfs_split_item 2013-11-11 21:51:02 -05:00
math.h Btrfs: cleanup duplicated division functions 2012-12-11 13:31:30 -05:00
ordered-data.c Btrfs: kill delay_iput arg to the wait_ordered functions 2013-09-21 11:05:27 -04:00
ordered-data.h Btrfs: kill delay_iput arg to the wait_ordered functions 2013-09-21 11:05:27 -04:00
orphan.c btrfs: replace many BUG_ONs with proper error handling 2012-03-22 11:52:54 +01:00
print-tree.c btrfs: drop unused parameter from btrfs_item_nr 2013-11-11 21:50:48 -05:00
print-tree.h btrfs: make static code static & remove dead code 2013-05-06 15:55:23 -04:00
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 Btrfs: RAID5 and RAID6 2013-02-01 14:24:23 -05:00
rcu-string.h Btrfs: use rcu to protect device->name 2012-06-14 21:29:16 -04:00
reada.c Btrfs: fix reada debug code compilation 2013-05-06 15:54:55 -04:00
relocation.c Btrfs: fix BUG_ON() casued by the reserved space migration 2013-11-11 21:54:28 -05:00
root-tree.c Btrfs: insert orphan roots into fs radix tree 2013-10-10 21:30:53 -04:00
scrub.c Btrfs: improve replacing nocow extents 2013-09-21 11:05:26 -04:00
send.c btrfs: drop unused parameter from btrfs_item_nr 2013-11-11 21:50:48 -05:00
send.h btrfs: make static code static & remove dead code 2013-05-06 15:55:23 -04:00
struct-funcs.c Btrfs: rewrite BTRFS_SETGET_FUNCS 2012-07-23 16:28:06 -04:00
super.c Btrfs: add a sanity test for btrfs_split_item 2013-11-11 21:51:02 -05:00
sysfs.c btrfs: fixup/remove module.h usage as required 2013-03-01 15:01:01 -05:00
transaction.c Btrfs: fix BUG_ON() casued by the reserved space migration 2013-11-11 21:54:28 -05:00
transaction.h Btrfs: fix BUG_ON() casued by the reserved space migration 2013-11-11 21:54:28 -05:00
tree-defrag.c btrfs: remove cache only arguments from defrag path 2013-02-20 12:59:36 -05:00
tree-log.c Btrfs: drop dir i_size when adding new names on replay 2013-09-21 11:05:25 -04:00
tree-log.h btrfs: make static code static & remove dead code 2013-05-06 15:55:23 -04:00
ulist.c Btrfs: fix crash regarding to ulist_add_merge 2013-07-02 11:50:59 -04:00
ulist.h Btrfs: add a rb_tree to improve performance of ulist search 2013-05-06 15:54:44 -04:00
uuid-tree.c Btrfs: check UUID tree during mount if required 2013-09-01 08:15:58 -04:00
volumes.c Merge branch 'for-linus' into for-linus-3.12 2013-10-05 10:51:32 -04:00
volumes.h Btrfs: add btrfs_alloc_device and switch to it 2013-09-01 08:16:04 -04:00
xattr.c btrfs: make static code static & remove dead code 2013-05-06 15:55:23 -04:00
xattr.h
zlib.c btrfs: fix message printing 2012-10-09 09:19:57 -04:00