mirror_zfs/include
Alexander Motin 05a7348a7e
RAIDZ: Use cache blocking during parity math
RAIDZ parity is calculated by adding data one column at a time.  It
works OK for small blocks, but for large blocks results of previous
addition may already be evicted from CPU caches to main memory, and
in addition to extra memory write require extra read to get it back.

This patch splits large parity operations into 64KB chunks, that
should in most cases fit into CPU L2 caches from the last decade.
I haven't touched more complicated cases of data reconstruction to
not over complicate the code.  Those should be relatively rare.

My tests on Xeon Gold 6242R CPU with 1MB of L2 cache per core show
up to 10/20% memory traffic reduction when writing to 4-wide RAIDZ/
RAIDZ2 blocks of ~4MB and up.  Older CPUs with 256KB of L2 cache
should see the effect even on smaller blocks.  Wider vdevs may need
bigger blocks to be affected.

Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes #15448
2023-10-30 14:54:27 -07:00
..
os ZIL: Cleanup sync and commit handling 2023-10-30 14:51:56 -07:00
sys RAIDZ: Use cache blocking during parity math 2023-10-30 14:54:27 -07:00
.gitignore OpenZFS restructuring - move platform specific sources 2019-09-06 11:26:26 -07:00
cityhash.h libzfs: convert to -fvisibility=hidden 2021-06-03 13:17:55 -07:00
libnvpair.h nvpair: Constify string functions 2023-03-14 15:25:50 -07:00
libuutil_common.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
libuutil_impl.h libuutil: deobfuscate internal pointers 2022-11-03 09:57:05 -07:00
libuutil.h Cleanup: Remove unused uu_pname code 2022-09-19 17:33:52 -07:00
libzfs_core.h Teach zpool scrub to scrub only blocks in error log 2023-05-18 11:59:42 -07:00
libzfs.h Add '-u' - nomount flag for zfs set 2023-10-02 16:58:54 -07:00
libzfsbootenv.h lib{efi,avl,share,tpool,zfs_core,zfsbootenv,zutil}: -fvisibility=hidden 2021-06-09 17:04:32 -07:00
libzutil.h Fix ZED auto-replace for VDEVs using by-id paths 2023-10-20 09:29:02 -07:00
Makefile.am Implementation of block cloning for ZFS 2023-03-10 11:59:53 -08:00
thread_pool.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfeature_common.h Increase limit of redaction list by using spill block 2023-08-26 11:34:43 -07:00
zfs_comutil.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_deleg.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_fletcher.h Drop lying to the compiler in the fletcher4 code 2023-03-24 10:29:19 -07:00
zfs_namecheck.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_prop.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00