mirror_zfs/module
Alexander Motin f7e6dcc68d Relax zfs_vnops_read_chunk_size limitations
It makes no sense to limit read size below the block size, since
DMU will any way consume resources for the whole block, while the
current zfs_vnops_read_chunk_size is only 1MB, which is smaller
that maximum block size of 16MB.  Plus in case of misaligned
Uncached I/O the buffer may get evicted between the chunks,
requiring repeating I/Os.

On 64-bit platforms increase zfs_vnops_read_chunk_size to 32MB.
It allows to less depend on speculative prefetcher if application
requests specific size, first not waiting for prefetcher to start
and later not prefetching more than needed.

Also while there, we don't need to align reads to the chunk size,
but only to a block size, which is smaller and so more forgiving.

My profiles show ~4% of CPU time saving when reading 16MB blocks.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Igor Kozhukhov <ikozhukhov@gmail.com>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes #17415
2025-06-17 10:50:27 -07:00
..
avl SPDX: license tags: CDDL-1.0 2025-04-16 09:59:44 -07:00
icp Linux build: silence objtool warnings 2025-06-17 10:50:26 -07:00
lua SPDX: license tags: MIT 2025-04-16 09:59:44 -07:00
nvpair SPDX: license tags: CDDL-1.0 2025-04-16 09:59:44 -07:00
os FreeBSD: zfs_putpages: don't undirty pages until after write completes 2025-06-17 10:50:26 -07:00
unicode [2.3.2] uconv: add SPDX license tag 2025-04-16 09:59:45 -07:00
zcommon GCC 15: Fix unterminated-string-initialization (#17244) 2025-04-16 09:59:45 -07:00
zfs Relax zfs_vnops_read_chunk_size limitations 2025-06-17 10:50:27 -07:00
zstd SPDX: license tags: BSD-3-Clause OR GPL-2.0-only 2025-04-16 09:59:44 -07:00
.gitignore FreeBSD: Ignore symlink to i386 includes 2022-08-02 16:34:23 -07:00
Kbuild.in Linux build: always use objtool 2025-06-17 10:50:26 -07:00
Makefile.bsd freebsd: unbreak module/Makefile.bsd build on 15-CURRENT-arm64 2025-04-16 09:59:45 -07:00
Makefile.in Fix "make install" with DESTDIR set (#16995) 2025-02-28 00:42:29 +05:00