this is the new revision of the patch series to allow configuring the
entry size of the qcow2 L2 cache. Follow this link for the full
description from the first version:
https://lists.gnu.org/archive/html/qemu-block/2017-10/msg00458.html
And here are some numbers showing the performance improvements:
https://lists.gnu.org/archive/html/qemu-block/2017-12/msg00507.html
Regards,
Berto
Changes:
v4:
- Rebased on top of f24ee107a07f093bd7ed475dd48d7ba57ea3d8fe
- Patch 17: Fix typo in comment
- Patch 24: Rename discard_single_l2() to discard_in_l2_slice() [Max]
- Patch 25: Rename zero_single_l2() to zero_in_l2_slice() [Max]
- Patch 27: Add comment clarifying the l2_index variable [Max]
- Patch 30: Remove unneeded void * casts [Eric, Max]
- Patch 31: Use offset_to_l2_slice_index() instead of doing it manually [Max]
v3: https://lists.gnu.org/archive/html/qemu-block/2018-01/msg00635.html
- Rebased on top of 1867d97b372d452184c65e8fcc273cfc45937541
- Patch 2: Use QEMU_IS_ALIGNED() instead of doing the bit operations
manually [Eric]
- Patch 13: Clarify that l2_slice_size means size in entries, not
bytes [Eric].
- Patch 16-17: The previous code has been splitted into patches 16 and
17 for clarity.
- Patch 17: Use slice_size2 for storing the size of the slice in bytes
(keeping the existing convention used in l1_size2 or
refcount_table_size2)
- Patch 17: Flush the cache only once [Anton, Eric]
- Patch 17: Call l2_load() after qcow2_free_clusters() [Anton]
- Patch 18 [new]: Refactor the l2_load() call in get_cluster_table()
[Anton]
- Patch 19: Fix typo [Eric]
- Patch 26-27: The previous code has been splitted into patches 26 and
27 for clarity.
- Patch 27: Use slice_size2 for storing the size of the slice in bytes
- Patch 28-30: The previous code has been splitted into patches 28, 29
and 30 for clarity.
- Patch 30: Use slice_size2 for storing the size of the slice in bytes
- Patch 30: Replace bdrv_read/write() with bdrv_pread/pwrite() [Eric]
- Patch 30: Initialize l2_dirty inside the inner loop [Anton]
- Patch 36: Fix maybe-uninitialized warning of l2_cache_entry_size
[Anton]
- Patch 36: Make MIN_L2_CACHE_SIZE the minimum number of cache
entries, not clusters [Anton]
- Patch 36: Add l2-cache-entry-size to BlockdevOptionsQcow2 [Eric]
- Patch 37-39: New iotests.
v2: https://lists.gnu.org/archive/html/qemu-block/2017-12/msg00507.html
- Rebased after the v2.11.0 release.
- Patch 2: Adjust the unaligned access check introduce by Max in 4efb1f7c612
- Patch 18: Prevent overflow when computing bytes_available in
qcow2_get_cluster_offset()
- Patch 31: Fix typo in error message in read_cache_sizes()
- Patch 32 [new]: Add test for l2-cache-entry-size'
v1: https://lists.gnu.org/archive/html/qemu-block/2017-10/msg00458.html
- Initial version
Here's the ouput of git backport-diff against v3:
Key:
[] : patches are identical
[] : number of functional differences between upstream/downstream patch
[down] : patch is downstream-only
The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively
001/39:[] [--] 'qcow2: Fix documentation of get_cluster_table()'
002/39:[] [--] 'qcow2: Add table size field to Qcow2Cache'
003/39:[] [--] 'qcow2: Remove BDS parameter from
qcow2_cache_get_table_addr()'
004/39:[] [--] 'qcow2: Remove BDS parameter from
qcow2_cache_get_table_idx()'
005/39:[] [--] 'qcow2: Remove BDS parameter from
qcow2_cache_table_release()'
006/39:[] [--] 'qcow2: Remove BDS parameter from
qcow2_cache_entry_mark_dirty()'
007/39:[] [--] 'qcow2: Remove BDS parameter from qcow2_cache_put()'
008/39:[] [--] 'qcow2: Remove BDS parameter from qcow2_cache_destroy()'
009/39:[] [--] 'qcow2: Remove BDS parameter from qcow2_cache_clean_unused()'
010/39:[] [--] 'qcow2: Remove BDS parameter from qcow2_cache_discard()'
011/39:[] [--] 'qcow2: Remove BDS parameter from
qcow2_cache_is_table_offset()'
012/39:[] [--] 'qcow2: Add offset_to_l1_index()'
013/39:[] [--] 'qcow2: Add l2_slice_size field to BDRVQcow2State'
014/39:[] [--] 'qcow2: Add offset_to_l2_slice_index()'
015/39:[] [--] 'qcow2: Update l2_load() to support L2 slices'
016/39:[] [--] 'qcow2: Prepare l2_allocate() for adding L2 slice support'
017/39:[0002] [FC] 'qcow2: Update l2_allocate() to support L2 slices'
018/39:[] [--] 'qcow2: Refactor get_cluster_table()'
019/39:[] [--] 'qcow2: Update get_cluster_table() to support L2 slices'
020/39:[] [--] 'qcow2: Update qcow2_get_cluster_offset() to support L2
slices'
021/39:[] [--] 'qcow2: Update qcow2_alloc_cluster_link_l2() to support L2
slices'
022/39:[] [--] 'qcow2: Update handle_copied() to support L2 slices'
023/39:[] [--] 'qcow2: Update handle_alloc() to support L2 slices'
024/39:[0012] [FC] 'qcow2: Update discard_single_l2() to support L2 slices'
025/39:[0008] [FC] 'qcow2: Update
