mirror_zfs/module
Brian Behlendorf b0319c1faa OpenZFS 7143 - dbuf_read() creates unnecessary zio_root() for bonus buf
dbuf_read() creates a zio_root() to track and wait for all the
zio's that may happen as part of this call. However, if the blkptr_t
for this buffer is NULL or a hole, we will not create any more zio's,
so this zio_root() is unnecessary. This is always the case when calling
dbuf_read() on a bonus buffer, because it has no blkptr (it's part of
the containing dnode). For workloads that read a lot of bonus buffers
(e.g. file creation and removal), creating and destroying these
unnecessary zio's can decrease performance by around 3%.

The fix is to only create/destroy the zio_root() in dbuf_read() if
the blkptr is not NULL and not a hole.

Changes sponsored by Intel Corp.

Authored by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by:  Alex Zhuravlev <alexey.zhuravlev@intel.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue openzfs/openzfs#137
Closes #4803 
Closes #5382
2016-12-01 16:50:11 -07:00
..
avl Fix uninitialized variable in avl_add() 2016-07-25 14:21:34 -07:00
icp Add TASKQID_INVALID 2016-11-02 12:14:45 -07:00
nvpair Fix file permissions 2016-10-08 14:57:56 -07:00
unicode Build user-space with different gcc optimization levels 2016-08-09 14:40:35 -07:00
zcommon DLPX-44812 integrate EP-220 large memory scalability 2016-11-29 14:34:27 -08:00
zfs OpenZFS 7143 - dbuf_read() creates unnecessary zio_root() for bonus buf 2016-12-01 16:50:11 -07:00
zpios kmem_zalloc with KM_SLEEP will never return NULL 2016-09-01 11:39:45 -07:00
.gitignore module/.gitignore: Add *.dwo (#4580) 2016-05-02 09:07:04 -07:00
Makefile.in Illumos Crypto Port module added to enable native encryption in zfs 2016-07-20 10:43:30 -07:00