mirror_zfs/module
Alexander Motin 1c0c729ab4
Several sorted scrub optimizations
- Reduce size and comparison complexity of q_exts_by_size B-tree.
Previous code used two 64-bit divisions and many other operations to
compare two B-tree elements.  It created enormous overhead.  This
implementation moves the math to the upper level and stores the score
in the B-tree elements themselves.  Since all that we need to store in
that B-tree is the extent score and offset, those can fit into single
8 byte value instead of 24 bytes of q_exts_by_addr element and can be
compared with single operation.
 - Better decouple secondary tree logic from main range_tree by moving
rt_btree_ops and related functions into dsl_scan.c as ext_size_ops.
Those functions are very small to worry about the code duplication and
range_tree does not need to know details such as rt_btree_compare.
 - Instead of accounting number of pending bytes per pool, that needs
atomic on global variable per block, account the number of non-empty
per-vdev queues, that change much more rarely.
 - When extent scan is interrupted by TXG end, continue it in the next
TXG instead of selecting next best extent.  It allows to avoid leaving
one truncated (and so likely not the best any more) extent each TXG.

On top of some other optimizations this saves about 1.5 minutes out of
10 to scrub pool of 12 SSDs, storing 1.5TB of 4KB zvol blocks.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tom Caputi <caputit1@tcnj.edu>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes #13576
2022-06-24 09:50:37 -07:00
..
avl AVL: Remove obsolete branching optimizations 2022-06-09 15:27:36 -07:00
icp Fix memory allocation issue for BLAKE3 context 2022-06-21 14:32:09 -07:00
lua linux: module: weld all but spl.ko into zfs.ko 2022-04-20 13:28:24 -07:00
nvpair linux: module: weld all but spl.ko into zfs.ko 2022-04-20 13:28:24 -07:00
os FreeBSD: Improve crypto_dispatch() handling 2022-06-17 15:38:51 -07:00
unicode linux: module: weld all but spl.ko into zfs.ko 2022-04-20 13:28:24 -07:00
zcommon Introduce BLAKE3 checksums as an OpenZFS feature 2022-06-08 15:55:57 -07:00
zfs Several sorted scrub optimizations 2022-06-24 09:50:37 -07:00
zstd Tiered early abort, zstd edition 2022-05-24 09:43:22 -07:00
.gitignore Cleanup linux module kbuild files 2020-06-10 09:24:15 -07:00
Kbuild.in Add support for ARCH=um for x86 sub-architectures 2022-06-15 14:22:52 -07:00
Makefile.bsd Introduce BLAKE3 checksums as an OpenZFS feature 2022-06-08 15:55:57 -07:00
Makefile.in autoconf: use include directives instead of recursing down lib 2022-05-10 10:18:11 -07:00