issue-4547: call IMixedBlockVisitor::Accept once for a merged block group instead of calling Accept for each block separately - prerequisite for subsequent performance improvement

[SvartMetal]

#4547

Currently it improves only mixed blocks benchmark, e2e read performance will be improved in subsequent PRs

Before:

svartmetal@svartmetal-ivm:~/nbs-github2/cloud/filestore/libs/storage/tablet/model/bench$ ./bench -b 180
----------- TMixedBlocks_FindBlocksWithoutDeletionMarkers ---------------
 samples:       2165
 iterations:    2895621
 iterations hr:    2.9M
 run time:      20.01680449
 per iteration: 16560.55141 (16.6K) cycles
----------- TMixedBlocks_FindBlocksWithOneDeletionMarker ---------------
 samples:       2161
 iterations:    2886003
 iterations hr:    2.89M
 run time:      20.00291087
 per iteration: 16608.40688 (16.6K) cycles
----------- TMixedBlocks_FindBlocksWithOneDeletionMarkerAtTheEnd ---------------
 samples:       2163
 iterations:    2890810
 iterations hr:    2.89M
 run time:      20.01441892
 per iteration: 16588.39107 (16.6K) cycles
----------- TMixedBlocks_FindBlocksWithMergedDeletionMarkers ---------------
 samples:       2161
 iterations:    2886003
 iterations hr:    2.89M
 run time:      20.01131554
 per iteration: 16623.08515 (16.6K) cycles
----------- TMixedBlocks_FindBlocksWithMergedDeletionMarkersAtTheEnd ---------------
 samples:       2160
 iterations:    2883601
 iterations hr:    2.88M
 run time:      20.00057149
 per iteration: 16619.07255 (16.6K) cycles
----------- TMixedBlocks_FindBlocksWithMixedDeletionMarkers ---------------
 samples:       1427
 iterations:    1258491
 iterations hr:    1.26M
 run time:      20.01632004
 per iteration: 38107.9914 (38.1K) cycles
----------- TMixedBlocks_FindBlocksWithMixedDeletionMarkersAtTheEnd ---------------
 samples:       1417
 iterations:    1241100
 iterations hr:    1.24M
 run time:      20.01088124
 per iteration: 38633.37401 (38.6K) cycles
----------- TMixedBlocks_FindSingleBlockWithoutDeletionMarkers ---------------
 samples:       26588
 iterations:    436409196
 iterations hr:    436M
 run time:      20.00404313
 per iteration: 109.4292453 cycles
----------- TMixedBlocks_FindSingleBlockWithMergedDeletionMarkers ---------------
 samples:       25083
 iterations:    388382385
 iterations hr:    388M
 run time:      20.00353224
 per iteration: 123.1323023 cycles

After:

svartmetal@svartmetal-ivm:~/nbs-github2/cloud/filestore/libs/storage/tablet/model/bench$ ./bench -b 180
----------- TMixedBlocks_FindBlocksWithoutDeletionMarkers ---------------
 samples:       4050
 iterations:    10131751
 iterations hr:    10.1M
 run time:      20.00187285
 per iteration: 4738.737611 cycles
----------- TMixedBlocks_FindBlocksWithOneDeletionMarker ---------------
 samples:       4050
 iterations:    10127250
 iterations hr:    10.1M
 run time:      20.00327768
 per iteration: 4748.897586 cycles
----------- TMixedBlocks_FindBlocksWithOneDeletionMarkerAtTheEnd ---------------
 samples:       4055
 iterations:    10154271
 iterations hr:    10.2M
 run time:      20.00105817
 per iteration: 4741.04696 cycles
----------- TMixedBlocks_FindBlocksWithMergedDeletionMarkers ---------------
 samples:       4048
 iterations:    10118251
 iterations hr:    10.1M
 run time:      20.00224432
 per iteration: 4752.696327 cycles
----------- TMixedBlocks_FindBlocksWithMergedDeletionMarkersAtTheEnd ---------------
 samples:       4058
 iterations:    10167795
 iterations hr:    10.2M
 run time:      20.00901032
 per iteration: 4736.18014 cycles
----------- TMixedBlocks_FindBlocksWithMixedDeletionMarkers ---------------
 samples:       1591
 iterations:    1563796
 iterations hr:    1.56M
 run time:      20.01774946
 per iteration: 30671.11588 (30.7K) cycles
----------- TMixedBlocks_FindBlocksWithMixedDeletionMarkersAtTheEnd ---------------
 samples:       1589
 iterations:    1560261
 iterations hr:    1.56M
 run time:      20.00151794
 per iteration: 30709.41771 (30.7K) cycles
----------- TMixedBlocks_FindSingleBlockWithoutDeletionMarkers ---------------
 samples:       27506
 iterations:    467063766
 iterations hr:    467M
 run time:      20.00279161
 per iteration: 105.2425582 cycles
----------- TMixedBlocks_FindSingleBlockWithMergedDeletionMarkers ---------------
 samples:       25619
 iterations:    405170811
 iterations hr:    405M
 run time:      20.00347144
 per iteration: 118.110906 cycles

[github-actions]

Note

This is an automated comment that will be appended during run.

🔴 linux-x86_64-relwithdebinfo: some tests FAILED for commit 116e446.

TESTS	PASSED	ERRORS	FAILED	FAILED BUILD	SKIPPED	MUTED?
10227	10225	0	1	0	1	0

🟢 linux-x86_64-relwithdebinfo: all tests PASSED for commit 116e446.

TESTS	PASSED	ERRORS	FAILED	FAILED BUILD	SKIPPED	MUTED?
45	45	0	0	0	0	0

[github-actions]

Note

This is an automated comment that will be appended during run.

🟢 linux-x86_64-relwithdebinfo: all tests PASSED for commit 54dc53b.

TESTS	PASSED	ERRORS	FAILED	FAILED BUILD	SKIPPED	MUTED?
10235	10234	0	0	0	1	0

[github-actions]

Note

This is an automated comment that will be appended during run.

🔴 linux-x86_64-relwithdebinfo: some tests FAILED for commit df16de8.

TESTS	PASSED	ERRORS	FAILED	FAILED BUILD	SKIPPED	MUTED?
10235	10233	0	1	0	1	0

🟢 linux-x86_64-relwithdebinfo: all tests PASSED for commit df16de8.

TESTS	PASSED	ERRORS	FAILED	FAILED BUILD	SKIPPED	MUTED?
2	2	0	0	0	0	0