mirror_zfs/module
Alexander Motin 5e5fd0a178
Speculative prefetch for reordered requests
Before this change speculative prefetcher was able to detect a stream
only if all of its accesses are perfectly sequential.  It was easy to
implement and is perfectly fine for single-threaded applications.
Unfortunately multi-threaded network servers, such as iSCSI, SMB or
NFS usually have plenty of threads and may often reorder requests,
preventing successful speculation and prefetch.

This change allows speculative prefetcher to detect streams even if
requests are reordered by introducing a list of 9 non-contiguous
ranges up to 16MB ahead of current stream position and filling the
gaps as more requests arrive.  It also allows stream to proceed
even with holes up to a certain configurable threshold (25%).

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes #16022
2024-04-08 15:13:27 -07:00
..
avl Suppress Clang Static Analyzer false positive in the AVL tree code. 2023-03-08 13:51:21 -08:00
icp module/icp/asm-arm/sha2: enable non-SIMD asm kernels on armv5/6 2023-12-05 12:01:09 -08:00
lua LUA: Backport CVE-2020-24370's patch 2024-02-07 11:53:05 -08:00
nvpair xdr: header cleanup 2024-04-03 15:13:27 -07:00
os vdev_disk: ensure trim errors are returned immediately 2024-04-08 11:50:24 -07:00
unicode Illumos #15286: do_composition() needs sign awareness 2023-01-05 11:16:21 -08:00
zcommon Add slow disk diagnosis to ZED 2024-02-08 09:19:52 -08:00
zfs Speculative prefetch for reordered requests 2024-04-08 15:13:27 -07:00
zstd Resolve WS-2021-0184 vulnerability in zstd 2023-02-02 15:12:51 -08:00
.gitignore FreeBSD: Ignore symlink to i386 includes 2022-08-02 16:34:23 -07:00
Kbuild.in ddt: lift dedup stats out to separate file 2024-02-15 11:45:05 -08:00
Makefile.bsd Makefile.bsd: sort and cleanup source file list 2024-04-03 15:49:22 -07:00
Makefile.in check-zstd-symbols: also ignore __pfx_ symbols 2023-09-18 09:08:41 -07:00