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mirror of https://github.com/octoleo/restic.git synced 2024-12-23 19:38:57 +00:00
restic/changelog/unreleased/pull-2781
greatroar 7bda28f31f Chaining hash table for repository.Index
These are faster to construct but slower to access. The allocation rate
is halved, the peak memory usage almost halved compared to standard map.

Benchmark results on linux/amd64, -benchtime=3s -count=20:

name                                            old time/op    new time/op    delta
PackerManager-8                                    178ms ± 0%     178ms ± 0%     ~     (p=0.231 n=20+20)
DecodeIndex-8                                      4.54s ± 0%     4.30s ± 0%   -5.20%  (p=0.000 n=18+17)
DecodeIndexParallel-8                              4.54s ± 0%     4.30s ± 0%   -5.22%  (p=0.000 n=19+18)
IndexHasUnknown-8                                 44.4ns ± 5%    50.5ns ±11%  +13.82%  (p=0.000 n=19+17)
IndexHasKnown-8                                   48.3ns ± 0%    51.5ns ±12%   +6.68%  (p=0.001 n=16+20)
IndexAlloc-8                                       758ms ± 1%     616ms ± 1%  -18.69%  (p=0.000 n=19+19)
IndexAllocParallel-8                               234ms ± 3%     204ms ± 2%  -12.60%  (p=0.000 n=20+18)
MasterIndexLookupSingleIndex-8                     122ns ± 0%     145ns ± 9%  +18.44%  (p=0.000 n=14+20)
MasterIndexLookupMultipleIndex-8                   369ns ± 2%     429ns ± 8%  +16.27%  (p=0.000 n=20+20)
MasterIndexLookupSingleIndexUnknown-8             68.4ns ± 5%    74.9ns ±13%   +9.47%  (p=0.000 n=20+20)
MasterIndexLookupMultipleIndexUnknown-8            315ns ± 3%     369ns ±11%  +17.14%  (p=0.000 n=20+20)
MasterIndexLookupParallel/known,indices=5-8        743ns ± 1%     816ns ± 2%   +9.87%  (p=0.000 n=17+17)
MasterIndexLookupParallel/unknown,indices=5-8      238ns ± 1%     260ns ± 2%   +9.14%  (p=0.000 n=19+20)
MasterIndexLookupParallel/known,indices=10-8      1.01µs ± 3%    1.11µs ± 2%   +9.79%  (p=0.000 n=19+20)
MasterIndexLookupParallel/unknown,indices=10-8     222ns ± 0%     269ns ± 2%  +20.83%  (p=0.000 n=16+20)
MasterIndexLookupParallel/known,indices=20-8      1.06µs ± 2%    1.19µs ± 2%  +12.95%  (p=0.000 n=19+18)
MasterIndexLookupParallel/unknown,indices=20-8     413ns ± 1%     530ns ± 1%  +28.19%  (p=0.000 n=18+20)
SaveAndEncrypt-8                                  30.2ms ± 1%    30.4ms ± 0%   +0.71%  (p=0.000 n=19+19)
LoadTree-8                                         540µs ± 1%     576µs ± 1%   +6.73%  (p=0.000 n=20+20)
LoadBlob-8                                        5.64ms ± 0%    5.64ms ± 0%     ~     (p=0.883 n=18+17)
LoadAndDecrypt-8                                  5.93ms ± 0%    5.95ms ± 1%     ~     (p=0.247 n=20+19)
LoadIndex-8                                       25.1ms ± 0%    24.5ms ± 1%   -2.54%  (p=0.000 n=18+17)

name                                            old speed      new speed      delta
PackerManager-8                                  296MB/s ± 0%   296MB/s ± 0%     ~     (p=0.229 n=20+20)
SaveAndEncrypt-8                                 139MB/s ± 1%   138MB/s ± 0%   -0.71%  (p=0.000 n=19+19)
LoadBlob-8                                       177MB/s ± 0%   177MB/s ± 0%     ~     (p=0.890 n=18+17)
LoadAndDecrypt-8                                 169MB/s ± 0%   168MB/s ± 1%     ~     (p=0.227 n=20+19)

name                                            old alloc/op   new alloc/op   delta
PackerManager-8                                   91.8kB ± 0%    91.8kB ± 0%     ~     (p=0.772 n=12+19)
IndexAlloc-8                                       786MB ± 0%     400MB ± 0%  -49.04%  (p=0.000 n=20+18)
IndexAllocParallel-8                               786MB ± 0%     401MB ± 0%  -49.04%  (p=0.000 n=19+15)
SaveAndEncrypt-8                                  21.0MB ± 0%    21.0MB ± 0%   +0.00%  (p=0.000 n=19+19)

name                                            old allocs/op  new allocs/op  delta
PackerManager-8                                    1.41k ± 0%     1.41k ± 0%     ~     (all equal)
IndexAlloc-8                                        977k ± 0%      907k ± 0%   -7.18%  (p=0.000 n=20+20)
IndexAllocParallel-8                                977k ± 0%      907k ± 0%   -7.17%  (p=0.000 n=19+15)
SaveAndEncrypt-8                                    73.0 ± 0%      73.0 ± 0%     ~     (all equal)
2020-07-19 13:58:22 +02:00

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Enhancement: Reduce memory consumption of in-memory index
We've improved how the index is stored in memory.
This change can reduce memory usage for large repositories by up to 50%
(depending on the operation).
https://github.com/restic/restic/pull/2781
https://github.com/restic/restic/pull/2812