TrueCloudLab/restic
16
0
Fork 3
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Replace siphash by hash/maphash

Browse source 
In Go 1.17.1, maphash has become quite a bit faster than siphash, so we
can drop one third-party dependency. maphash is just an interface to the
standard Go map's hash function, which we already trust for other use
cases.

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

name                                             old time/op    new time/op    delta
IndexHasUnknown-8                                  50.6ns ±10%    41.0ns ±19%  -18.92%  (p=0.000 n=9+10)
IndexHasKnown-8                                    52.6ns ±12%    41.5ns ±12%  -21.13%  (p=0.000 n=9+10)
IndexMapHash-8                                     3.64µs ± 1%    2.00µs ± 0%  -45.09%  (p=0.000 n=10+9)
IndexAlloc-8                                        700ms ± 1%     601ms ± 6%  -14.18%  (p=0.000 n=8+10)
IndexAllocParallel-8                                205ms ± 5%     192ms ± 8%   -6.18%  (p=0.043 n=10+10)
MasterIndexAlloc-8                                  319ms ± 1%     279ms ± 5%  -12.58%  (p=0.000 n=10+10)
MasterIndexLookupSingleIndex-8                      156ns ± 8%     147ns ± 6%   -5.46%  (p=0.023 n=10+10)
MasterIndexLookupMultipleIndex-8                    150ns ± 7%     142ns ± 8%   -5.69%  (p=0.007 n=10+10)
MasterIndexLookupSingleIndexUnknown-8              74.4ns ± 6%    72.0ns ± 9%     ~     (p=0.175 n=10+9)
MasterIndexLookupMultipleIndexUnknown-8            67.4ns ± 9%    65.5ns ± 7%     ~     (p=0.340 n=9+9)
MasterIndexLookupParallel/known,indices=25-8        461ns ± 2%     445ns ± 2%   -3.49%  (p=0.000 n=10+10)
MasterIndexLookupParallel/unknown,indices=25-8      408ns ±11%     378ns ± 5%   -7.22%  (p=0.035 n=10+9)
MasterIndexLookupParallel/known,indices=50-8        479ns ± 1%     437ns ± 4%   -8.82%  (p=0.000 n=10+10)
MasterIndexLookupParallel/unknown,indices=50-8      406ns ± 8%     343ns ±15%  -15.44%  (p=0.001 n=10+10)
MasterIndexLookupParallel/known,indices=100-8       480ns ± 1%     455ns ± 5%   -5.15%  (p=0.000 n=8+10)
MasterIndexLookupParallel/unknown,indices=100-8     391ns ±18%     382ns ± 8%     ~     (p=0.315 n=10+10)
MasterIndexLookupBlobSize-8                        71.0ns ± 8%    57.2ns ±11%  -19.36%  (p=0.000 n=9+10)
PackerManager-8                                     254ms ± 1%     254ms ± 1%     ~     (p=0.285 n=15+15)

name                                             old speed      new speed      delta
IndexMapHash-8                                   1.12GB/s ± 1%  2.05GB/s ± 0%  +82.13%  (p=0.000 n=10+9)
PackerManager-8                                   208MB/s ± 1%   207MB/s ± 1%     ~     (p=0.281 n=15+15)

name                                             old alloc/op   new alloc/op   delta
IndexMapHash-8                                      0.00B          0.00B          ~     (all equal)
IndexAlloc-8                                        400MB ± 0%     400MB ± 0%     ~     (p=1.000 n=9+10)
IndexAllocParallel-8                                401MB ± 0%     401MB ± 0%   +0.00%  (p=0.000 n=10+10)
MasterIndexAlloc-8                                  258MB ± 0%     262MB ± 0%   +1.42%  (p=0.000 n=9+10)
PackerManager-8                                    73.1kB ± 0%    73.1kB ± 0%     ~     (p=0.382 n=13+13)

name                                             old allocs/op  new allocs/op  delta
IndexMapHash-8                                       0.00           0.00          ~     (all equal)
IndexAlloc-8                                         907k ± 0%      907k ± 0%   -0.00%  (p=0.000 n=10+10)
IndexAllocParallel-8                                 907k ± 0%      907k ± 0%   +0.00%  (p=0.009 n=10+10)
MasterIndexAlloc-8                                   327k ± 0%      317k ± 0%   -3.06%  (p=0.000 n=10+10)
PackerManager-8                                       744 ± 0%       744 ± 0%     ~     (all equal)
This commit is contained in:
greatroar 2021-09-17 12:38:17 +02:00
parent bf9c8771a4
commit 8d2996eaaa
4 changed files with 7 additions and 44 deletions
Download patch file Download diff file Expand all files Collapse all files

26
internal/repository/indexmap_test.go
View file

@ -107,32 +107,6 @@ func TestIndexMapForeachWithID(t *testing.T) {
}
}
func TestIndexMapHash(t *testing.T) {
t.Parallel()
var m1, m2 indexMap
id := restic.NewRandomID()
// Add to both maps to initialize them.
m1.add(id, 0, 0, 0)
m2.add(id, 0, 0, 0)
h1 := m1.hash(id)
h2 := m2.hash(id)
rtest.Equals(t, len(m1.buckets), len(m2.buckets)) // just to be sure
if h1 == h2 {
// The probability of the zero key should be 2^(-128).
if m1.key0 == 0 && m1.key1 == 0 {
t.Error("siphash key not set for m1")
}
if m2.key0 == 0 && m2.key1 == 0 {
t.Error("siphash key not set for m2")
}
}
}
func BenchmarkIndexMapHash(b *testing.B) {
var m indexMap
m.add(restic.ID{}, 0, 0, 0) // Trigger lazy initialization.