Illumos 6281 - prefetching should apply to 1MB reads

6281 prefetching should apply to 1MB reads
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Alexander Motin <mav@freebsd.org>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Reviewed by: Justin Gibbs <gibbs@scsiguy.com>
Reviewed by: Xin Li <delphij@freebsd.org>
Approved by: Gordon Ross <gordon.ross@nexenta.com>

References:
  https://www.illumos.org/issues/6281
  https://github.com/illumos/illumos-gate/commit/6328027

Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This commit is contained in:
George Wilson 2016-01-09 17:19:10 +01:00 committed by Brian Behlendorf
parent fe467e06fd
commit a6fb32b85a
2 changed files with 3 additions and 3 deletions

View File

@ -442,7 +442,7 @@ dmu_buf_hold_array_by_dnode(dnode_t *dn, uint64_t offset, uint64_t length,
}
if ((flags & DMU_READ_NO_PREFETCH) == 0 && read &&
length < zfetch_array_rd_sz) {
length <= zfetch_array_rd_sz) {
dmu_zfetch(&dn->dn_zfetch, blkid, nblks);
}
rw_exit(&dn->dn_struct_rwlock);

View File

@ -24,7 +24,7 @@
*/
/*
* Copyright (c) 2013, 2014 by Delphix. All rights reserved.
* Copyright (c) 2013, 2015 by Delphix. All rights reserved.
*/
#include <sys/zfs_context.h>
@ -50,7 +50,7 @@ unsigned int zfetch_max_streams = 8;
unsigned int zfetch_min_sec_reap = 2;
/* max bytes to prefetch per stream (default 8MB) */
unsigned int zfetch_max_distance = 8 * 1024 * 1024;
/* number of bytes in a array_read at which we stop prefetching (1MB) */
/* max number of bytes in an array_read in which we allow prefetching (1MB) */
unsigned long zfetch_array_rd_sz = 1024 * 1024;
typedef struct zfetch_stats {