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Kuan-Wei Chiu 0ddb5f0854 bcachefs: Optimize eytzinger0_sort() with bottom-up heapsort 
This optimization reduces the average number of comparisons required
from 2*n*log2(n) - 3*n + o(n) to n*log2(n) + 0.37*n + o(n). When n is
sufficiently large, it results in approximately 50% fewer comparisons.

Currently, eytzinger0_sort employs the textbook version of heapsort,
where during the heapify process, each level requires two comparisons
to determine the maximum among three elements. In contrast, the
bottom-up heapsort, during heapify, only compares two children at each
level until reaching a leaf node. Then, it backtracks from the leaf
node to find the correct position. Since heapify typically continues
until very close to the leaf node, the standard heapify requires about
2*log2(n) comparisons, while the bottom-up variant only needs log2(n)
comparisons.

The experimental data presented below is based on an array generated
by get_random_u32().

|   N   | comparisons(old) | comparisons(new) | time(old) | time(new) |
|-------|------------------|------------------|-----------|-----------|
| 10000 |     235381       |     136615       |  25545 us |  20366 us |
| 20000 |     510694       |     293425       |  31336 us |  18312 us |
| 30000 |     800384       |     457412       |  35042 us |  27386 us |
| 40000 |    1101617       |     626831       |  48779 us |  38253 us |
| 50000 |    1409762       |     799637       |  62238 us |  46950 us |
| 60000 |    1721191       |     974521       |  75588 us |  58367 us |
| 70000 |    2038536       |    1152171       |  90823 us |  68778 us |
| 80000 |    2362958       |    1333472       | 104165 us |  78625 us |
| 90000 |    2690900       |    1516065       | 116111 us |  89573 us |
| 100000|    3019413       |    1699879       | 133638 us | 100998 us |

Refs:
  BOTTOM-UP-HEAPSORT, a new variant of HEAPSORT beating, on an average,
  QUICKSORT (if n is not very small)
  Ingo Wegener
  Theoretical Computer Science, 118(1); Pages 81-98, 13 September 1993
  https://doi.org/10.1016/0304-3975(93)90364-Y

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-05-08 17:29:18 -04:00
..
9p fs/9p: mitigate inode collisions 2024-04-22 15:34:27 +00:00
adfs mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
affs affs: remove SLAB_MEM_SPREAD flag usage 2024-02-26 11:36:28 +01:00
afs afs: Fix occasional rmdir-then-VNOVNODE with generic/011 2024-03-14 12:13:21 +01:00
autofs dcache stuff for this cycle 2024-01-11 20:11:35 -08:00
bcachefs bcachefs: Optimize eytzinger0_sort() with bottom-up heapsort 2024-05-08 17:29:18 -04:00
befs mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
bfs mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
btrfs for-6.9-rc5-tag 2024-04-24 09:22:51 -07:00
cachefiles cachefiles: fix memory leak in cachefiles_add_cache() 2024-02-20 09:46:07 +01:00
ceph ceph: switch to use cap_delay_lock for the unlink delay list 2024-04-11 22:56:28 +02:00
coda mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
configfs
cramfs fs,block: yield devices early 2024-03-27 13:17:15 +01:00
crypto fscrypt updates for 6.9 2024-03-12 13:17:36 -07:00
debugfs debugfs: fix wait/cancellation handling during remove 2024-03-07 22:08:15 +00:00
devpts fs: Remove the now superfluous sentinel elements from ctl_table array 2023-12-28 04:57:57 -08:00
dlm dlm for 6.9 2024-03-18 15:39:48 -07:00
ecryptfs Merge tag 'exportfs-6.9' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/cel/linux 2024-01-23 17:56:30 +01:00
efivarfs efivarfs: Drop 'duplicates' bool parameter on efivar_init() 2024-02-25 09:43:39 +01:00
efs efs: remove SLAB_MEM_SPREAD flag usage 2024-02-27 11:21:33 +01:00
erofs erofs: drop experimental warning for FSDAX 2024-03-25 10:48:15 +08:00
exfat Description for this pull request: 2024-03-21 09:47:12 -07:00
exportfs fs: Create a generic is_dot_dotdot() utility 2024-01-23 10:58:56 -05:00
ext2 \n 2024-03-13 14:30:58 -07:00
ext4 fs,block: yield devices early 2024-03-27 13:17:15 +01:00
f2fs fs,block: yield devices early 2024-03-27 13:17:15 +01:00
fat - Kuan-Wei Chiu has developed the well-named series "lib min_heap: Min 2024-03-14 18:03:09 -07:00
freevxfs mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
fuse cuse: add kernel-doc comments to cuse_process_init_reply() 2024-04-15 11:02:10 +02:00
gfs2 gfs2 fix 2024-03-25 10:53:39 -07:00
hfs hfs: really remove hfs_writepage 2023-12-29 11:58:34 -08:00
hfsplus vfs-6.9.misc 2024-03-11 09:38:17 -07:00
hostfs hostfs: use d_splice_alias() calling conventions to simplify failure exits 2023-12-21 12:51:00 -05:00
hpfs mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
hugetlbfs vfs-6.9.misc 2024-03-11 09:38:17 -07:00
iomap vfs-6.9.rw_hint 2024-03-04 18:35:21 +01:00
isofs mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
jbd2 jbd2: abort journal when detecting metadata writeback error of fs dev 2024-01-04 23:42:21 -05:00
jffs2 mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
jfs fs,block: yield devices early 2024-03-27 13:17:15 +01:00
kernfs kernfs: annotate different lockdep class for of->mutex of writable files 2024-04-14 06:55:46 -04:00
lockd NFSD 6.9 Release Notes 2024-03-12 14:27:37 -07:00
minix minix: remove SLAB_MEM_SPREAD flag usage 2024-02-27 11:21:32 +01:00
netfs netfs: Fix the pre-flush when appending to a file in writethrough mode 2024-04-26 14:56:18 +02:00
nfs NFS client updates for Linux 6.9 2024-03-16 11:44:00 -07:00
nfs_common
nfsd nfsd-6.9 fixes: 2024-04-25 09:31:06 -07:00
nilfs2 nilfs2: fix OOB in nilfs_set_de_type 2024-04-16 15:39:52 -07:00
nls
notify fanotify: allow freeze when waiting response for permission events 2024-03-07 12:59:51 +01:00
ntfs3 ntfs3: add legacy ntfs file operations 2024-04-23 09:39:07 +02:00
ocfs2 - Kuan-Wei Chiu has developed the well-named series "lib min_heap: Min 2024-03-14 18:03:09 -07:00
omfs
openpromfs openpromfs: remove SLAB_MEM_SPREAD flag usage 2024-02-27 11:21:32 +01:00
orangefs Julia Lawall reported this null pointer dereference, this should fix it. 2024-02-14 15:57:53 -05:00
overlayfs ovl: relax WARN_ON in ovl_verify_area() 2024-03-17 15:59:41 +02:00
proc mm: support page_mapcount() on page_has_type() pages 2024-04-24 19:34:26 -07:00
pstore pstore/zone: Don't clear memory twice 2024-03-09 12:33:22 -08:00
qnx4 mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
qnx6 qnx6: remove SLAB_MEM_SPREAD flag usage 2024-02-27 11:21:32 +01:00
quota mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
ramfs ramfs: Initialize security of in-memory inodes 2024-01-26 09:08:16 -08:00
reiserfs fs,block: yield devices early 2024-03-27 13:17:15 +01:00
romfs fs,block: yield devices early 2024-03-27 13:17:15 +01:00
smb smb3: fix lock ordering potential deadlock in cifs_sync_mid_result 2024-04-25 12:49:50 -05:00
squashfs Squashfs: check the inode number is not the invalid value of zero 2024-04-16 15:39:50 -07:00
sysfs fs: sysfs: Fix reference leak in sysfs_break_active_protection() 2024-04-11 15:16:48 +02:00
sysv sysv: remove SLAB_MEM_SPREAD flag usage 2024-02-27 11:21:31 +01:00
tracefs eventfs: Fix kernel-doc comments to functions 2024-04-11 17:42:09 -04:00
ubifs This pull request contains updates for UBI and UBIFS: 2024-03-21 15:09:29 -07:00
udf mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
ufs mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
unicode
vboxsf vboxsf: explicitly deny setlease attempts 2024-04-03 16:06:39 +02:00
verity Networking changes for 6.9. 2024-03-12 17:44:08 -07:00
xfs Bug fixes for 6.9-rc3: 2024-04-06 09:14:18 -07:00
zonefs zonefs: Use str_plural() to fix Coccinelle warning 2024-04-10 07:23:47 +09:00
aio.c aio: Fix null ptr deref in aio_complete() wakeup 2024-04-05 11:20:28 +02:00
anon_inodes.c Merge branch 'kvm-guestmemfd' into HEAD 2023-11-14 08:31:31 -05:00
attr.c lsm/stable-6.9 PR 20240312 2024-03-12 20:03:34 -07:00
backing-file.c fs: Use KMEM_CACHE instead of kmem_cache_create 2024-02-02 13:11:50 +01:00
bad_inode.c
binfmt_elf_fdpic.c binfmt: replace deprecated strncpy 2024-03-21 20:20:52 -07:00
binfmt_elf_test.c
binfmt_elf.c
binfmt_flat.c
binfmt_misc.c execve updates for v6.7-rc1 2023-10-30 19:28:19 -10:00
binfmt_script.c
buffer.c vfs-6.9.iomap 2024-03-11 10:07:03 -07:00
char_dev.c As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
compat_binfmt_elf.c
coredump.c iov_iter: get rid of 'copy_mc' flag 2024-03-06 10:52:12 +01:00
d_path.c
dax.c fs : Fix warning using plain integer as NULL 2023-11-18 15:00:01 +01:00
dcache.c vfs-6.9.misc 2024-03-11 09:38:17 -07:00
direct-io.c block, fs: Restore the per-bio/request data lifetime fields 2024-02-06 14:31:05 +01:00
drop_caches.c
eventfd.c eventfd: strictly check the count parameter of eventfd_write to avoid inputting illegal strings 2024-02-08 10:12:26 +01:00
eventpoll.c Networking changes for 6.9. 2024-03-12 17:44:08 -07:00
exec.c execve fixes for v6.9-rc2 2024-03-27 09:57:30 -07:00
fcntl.c vfs-6.9.iomap 2024-03-11 10:07:03 -07:00
fhandle.c do_sys_name_to_handle(): use kzalloc() to fix kernel-infoleak 2024-01-22 15:33:38 +01:00
file_table.c lsm/stable-6.9 PR 20240312 2024-03-12 20:03:34 -07:00
file.c file: remove __receive_fd() 2023-12-12 14:24:14 +01:00
filesystems.c
fs_context.c
fs_parser.c __fs_parse: Correct a documentation comment 2024-02-02 13:11:50 +01:00
fs_pin.c
fs_struct.c
fs_types.c
fs-writeback.c writeback: move wb_wakeup_delayed defination to fs-writeback.c 2024-01-22 15:33:38 +01:00
fsopen.c
init.c
inode.c bcachefs updates for 6.9 2024-03-15 09:00:09 -07:00
internal.h pidfs: remove config option 2024-03-13 12:53:53 -07:00
ioctl.c fs: Return ENOTTY directly if FS_IOC_GETUUID or FS_IOC_GETFSSYSFSPATH fail 2024-04-09 12:03:49 +02:00
Kconfig - Sumanth Korikkar has taught s390 to allocate hotplug-time page frames 2024-03-14 17:43:30 -07:00
Kconfig.binfmt
kernel_read_file.c
libfs.c pidfs: remove config option 2024-03-13 12:53:53 -07:00
locks.c filelock: fix deadlock detection in POSIX locking 2024-02-20 09:53:33 +01:00
Makefile vfs-6.9.pidfd 2024-03-11 10:21:06 -07:00
mbcache.c vfs: remove SLAB_MEM_SPREAD flag usage 2024-02-27 11:21:31 +01:00
mnt_idmapping.c fs/mnt_idmapping.c: Return -EINVAL when no map is written 2024-02-08 10:12:37 +01:00
mount.h mounts: keep list of mounts in an rbtree 2023-11-18 14:56:16 +01:00
mpage.c block, fs: Restore the per-bio/request data lifetime fields 2024-02-06 14:31:05 +01:00
namei.c security: Place security_path_post_mknod() where the original IMA call was 2024-04-03 10:21:32 -07:00
namespace.c fs: relax mount_setattr() permission checks 2024-02-07 21:16:29 +01:00
nsfs.c pidfs: remove config option 2024-03-13 12:53:53 -07:00
open.c lsm/stable-6.9 PR 20240312 2024-03-12 20:03:34 -07:00
pidfs.c pidfs: remove config option 2024-03-13 12:53:53 -07:00
pipe.c fs/pipe: Convert to lockdep_cmp_fn 2024-02-02 13:11:49 +01:00
pnode.c mounts: keep list of mounts in an rbtree 2023-11-18 14:56:16 +01:00
pnode.h
posix_acl.c lsm/stable-6.9 PR 20240312 2024-03-12 20:03:34 -07:00
proc_namespace.c namespace: extract show_path() helper 2023-11-18 14:56:16 +01:00
read_write.c fsnotify: optionally pass access range in file permission hooks 2023-12-12 16:20:02 +01:00
readdir.c fsnotify: optionally pass access range in file permission hooks 2023-12-12 16:20:02 +01:00
remap_range.c remap_range: merge do_clone_file_range() into vfs_clone_file_range() 2024-02-06 17:07:21 +01:00
select.c fs/select: rework stack allocation hack for clang 2024-02-20 09:23:52 +01:00
seq_file.c
signalfd.c
splice.c fs: use splice_copy_file_range() inline helper 2023-12-12 16:20:02 +01:00
stack.c
stat.c vfs-6.8.mount 2024-01-08 10:57:34 -08:00
statfs.c
super.c fs,block: yield devices early 2024-03-27 13:17:15 +01:00
sync.c
sysctls.c fs: Remove the now superfluous sentinel elements from ctl_table array 2023-12-28 04:57:57 -08:00
timerfd.c
userfaultfd.c userfaultfd: use per-vma locks in userfaultfd operations 2024-02-22 15:27:20 -08:00
utimes.c
xattr.c evm: Move to LSM infrastructure 2024-02-15 23:43:47 -05:00