diff options
| author | Matthew Ahrens <[email protected]> | 2015-12-26 22:10:31 +0100 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2016-01-12 09:02:33 -0800 |
| commit | 7f60329a261bd48558a498fb10e9b29638eab33b (patch) | |
| tree | 5e6616fbac91442ce424ca44a8288bf9f46db3cc /man/man5 | |
| parent | ab5cbbd1078bf007b50b084bb31fd58c7c5652f4 (diff) | |
Illumos 5987 - zfs prefetch code needs work
5987 zfs prefetch code needs work
Reviewed by: Adam Leventhal <[email protected]>
Reviewed by: George Wilson <[email protected]>
Reviewed by: Paul Dagnelie <[email protected]>
Approved by: Gordon Ross <[email protected]>
References:
https://www.illumos.org/issues/5987 zfs prefetch code needs work
illumos/illumos-gate@cf6106c 5987 zfs prefetch code needs work
Porting notes:
- [module/zfs/dbuf.c]
- 5f6d0b6 Handle block pointers with a corrupt logical size
- [module/zfs/dmu_zfetch.c]
- c65aa5b Fix gcc missing parenthesis warnings
- 428870f Update core ZFS code from build 121 to build 141.
- 79c76d5 Change KM_PUSHPAGE -> KM_SLEEP
- b8d06fc Switch KM_SLEEP to KM_PUSHPAGE
- Account for ISO C90 - mixed declarations and code - warnings
- Module parameters (new/changed):
- Replaced zfetch_block_cap with zfetch_max_distance
(Max bytes to prefetch per stream (default 8MB; 8 * 1024 * 1024))
- Preserved zfs_prefetch_disable as 'int' for consistency with
existing Linux module options.
- [include/sys/trace_arc.h]
- Added new tracepoints
- DEFINE_ARC_BUF_HDR_EVENT(zfs_arc__sync__wait__for__async);
- DEFINE_ARC_BUF_HDR_EVENT(zfs_arc__demand__hit__predictive__prefetch);
- [man/man5/zfs-module-parameters.5]
- Updated man page
Ported-by: kernelOfTruth [email protected]
Signed-off-by: Brian Behlendorf <[email protected]>
Diffstat (limited to 'man/man5')
| -rw-r--r-- | man/man5/zfs-module-parameters.5 | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/man/man5/zfs-module-parameters.5 b/man/man5/zfs-module-parameters.5 index 6be382eac..eabd8ebe9 100644 --- a/man/man5/zfs-module-parameters.5 +++ b/man/man5/zfs-module-parameters.5 @@ -331,12 +331,12 @@ Default value: \fB1,048,576\fR. .sp .ne 2 .na -\fBzfetch_block_cap\fR (uint) +\fBzfetch_max_distance\fR (uint) .ad .RS 12n -Max number of blocks to prefetch at a time +Max bytes to prefetch per stream (default 8MB). .sp -Default value: \fB256\fR. +Default value: \fB8,388,608\fR. .RE .sp @@ -1246,7 +1246,10 @@ Default value: \fB52,428,800\fR. \fBzfs_prefetch_disable\fR (int) .ad .RS 12n -Disable all ZFS prefetching +This tunable disables predictive prefetch. Note that it leaves "prescient" +prefetch (e.g. prefetch for zfs send) intact. Unlike predictive prefetch, +prescient prefetch never issues i/os that end up not being needed, so it +can't hurt performance. .sp Use \fB1\fR for yes and \fB0\fR for no (default). .RE |