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339158 |
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03-Oct-2018 |
mav |
MFC r337567 (by mmacy): Performance optimization of AVL tree comparator functions
MFV: commit ee36c709c3d5f7040e1bd11f5c75318aa03e789f Author: Gvozden Neskovic <neskovic@gmail.com> Date: Sat Aug 27 20:12:53 2016 +0200
perf: 2.75x faster ddt_entry_compare() First 256bits of ddt_key_t is a block checksum, which are expected to be close to random data. Hence, on average, comparison only needs to look at first few bytes of the keys. To reduce number of conditional jump instructions, the result is computed as: sign(memcmp(k1, k2)).
Sign of an integer 'a' can be obtained as: `(0 < a) - (a < 0)` := {-1, 0, 1} , which is computed efficiently. Synthetic performance evaluation of original and new algorithm over 1G random keys on 2.6GHz Intel(R) Xeon(R) CPU E5-2660 v3:
old 6.85789 s new 2.49089 s
perf: 2.8x faster vdev_queue_offset_compare() and vdev_queue_timestamp_compare() Compute the result directly instead of using conditionals
perf: zfs_range_compare() Speedup between 1.1x - 2.5x, depending on compiler version and optimization level.
perf: spa_error_entry_compare() `bcmp()` is not suitable for comparator use. Use `memcmp()` instead.
perf: 2.8x faster metaslab_compare() and metaslab_rangesize_compare() perf: 2.8x faster zil_bp_compare() perf: 2.8x faster mze_compare() perf: faster dbuf_compare() perf: faster compares in spa_misc perf: 2.8x faster layout_hash_compare() perf: 2.8x faster space_reftree_compare() perf: libzfs: faster avl tree comparators perf: guid_compare() perf: dsl_deadlist_compare() perf: perm_set_compare() perf: 2x faster range_tree_seg_compare() perf: faster unique_compare() perf: faster vdev_cache _compare() perf: faster vdev_uberblock_compare() perf: faster fuid _compare() perf: faster zfs_znode_hold_compare()
Signed-off-by: Gvozden Neskovic <neskovic@gmail.com> Signed-off-by: Richard Elling <richard.elling@gmail.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #5033
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332525 |
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16-Apr-2018 |
mav |
MFC r329732: MFV r329502: 7614 zfs device evacuation/removal
illumos/illumos-gate@5cabbc6b49070407fb9610cfe73d4c0e0dea3e77
https://www.illumos.org/issues/7614: This project allows top-level vdevs to be removed from the storage pool with “zpool remove”, reducing the total amount of storage in the pool. This operation copies all allocated regions of the device to be removed onto other devices, recording the mapping from old to new location. After the removal is complete, read and free operations to the removed (now “indirect”) vdev must be remapped and performed at the new location on disk. The indirect mapping table is kept in memory whenever the pool is loaded, so there is minimal performance overhead when doing operations on the indirect vdev.
The size of the in-memory mapping table will be reduced when its entries become “obsolete” because they are no longer used by any block pointers in the pool. An entry becomes obsolete when all the blocks that use it are freed. An entry can also become obsolete when all the snapshots that reference it are deleted, and the block pointers that reference it have been “remapped” in all filesystems/zvols (and clones). Whenever an indirect block is written, all the block pointers in it will be “remapped” to their new (concrete) locations if possible. This process can be accelerated by using the “zfs remap” command to proactively rewrite all indirect blocks that reference indirect (removed) vdevs.
Note that when a device is removed, we do not verify the checksum of the data that is copied. This makes the process much faster, but if it were used on redundant vdevs (i.e. mirror or raidz vdevs), it would be possible to copy the wrong data, when we have the correct data on e.g. the other side of the mirror. Therefore, mirror and raidz devices can not be removed.
Reviewed by: Alex Reece <alex@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed by: John Kennedy <john.kennedy@delphix.com> Reviewed by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: Matthew Ahrens <mahrens@delphix.com> Reviewed by: Richard Laager <rlaager@wiktel.com> Reviewed by: Tim Chase <tim@chase2k.com> Approved by: Garrett D'Amore <garrett@damore.org> Author: Prashanth Sreenivasa <pks@delphix.com>
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258717 |
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28-Nov-2013 |
avg |
MFV r258371,r258372: 4101 metaslab_debug should allow for fine-grained control
4101 metaslab_debug should allow for fine-grained control 4102 space_maps should store more information about themselves 4103 space map object blocksize should be increased 4104 ::spa_space no longer works 4105 removing a mirrored log device results in a leaked object 4106 asynchronously load metaslab
illumos/illumos-gate@0713e232b7712cd27d99e1e935ebb8d5de61c57d
Note that some tunables have been removed and some new tunables have been added. Of particular note, FreeBSD-only knob vfs.zfs.space_map_last_hope is removed as it was a nop for some time now (after one of the previous merges from upstream).
MFC after: 11 days Sponsored by: HybridCluster [merge]
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