Commit Graph

12 Commits

Author SHA1 Message Date
Joe Tsai
d666bd8533
util/deephash: disambiguate hashing of AppendTo (#2483)
Prepend size to AppendTo output.

Fixes #2443

Signed-off-by: Joe Tsai <joetsai@digital-static.net>
2021-07-21 11:29:08 -07:00
Joe Tsai
23ad028414
util/deephash: include type as part of hash for interfaces (#2476)
A Go interface may hold any number of different concrete types.
Just because two underlying values hash to the same thing
does not mean the two values are identical if they have different
concrete types. As such, include the type in the hash.
2021-07-21 10:26:04 -07:00
Joe Tsai
9a0c8bdd20 util/deephash: make hash type opaque
The fact that Hash returns a [sha256.Size]byte leaks details about
the underlying hash implementation. This could very well be any other
hashing algorithm with a possible different block size.

Abstract this implementation detail away by declaring an opaque type
that is comparable. While we are changing the signature of UpdateHash,
rename it to just Update to reduce stutter (e.g., deephash.Update).

Signed-off-by: Joe Tsai <joetsai@digital-static.net>
2021-07-20 11:03:25 -07:00
Brad Fitzpatrick
ddb8726c98 util/deephash: don't reflect.Copy if element type is a defined uint8
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-07-07 11:58:04 -07:00
Brad Fitzpatrick
df176c82f5 util/deephash: skip alloc test under race detector
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-07-07 11:40:28 -07:00
Brad Fitzpatrick
6dc38ff25c util/deephash: optimize hashing of byte arrays, reduce allocs in Hash
name              old time/op    new time/op    delta
Hash-6               173µs ± 4%     101µs ± 3%   -41.69%  (p=0.000 n=10+9)
HashMapAcyclic-6     101µs ± 5%     105µs ± 3%    +3.52%  (p=0.001 n=9+10)
TailcfgNode-6       29.4µs ± 2%    16.4µs ± 3%   -44.25%  (p=0.000 n=8+10)

name              old alloc/op   new alloc/op   delta
Hash-6              3.60kB ± 0%    1.13kB ± 0%   -68.70%  (p=0.000 n=10+10)
HashMapAcyclic-6    2.53kB ± 0%    2.53kB ± 0%      ~     (p=0.137 n=10+8)
TailcfgNode-6         528B ± 0%        0B       -100.00%  (p=0.000 n=10+10)

name              old allocs/op  new allocs/op  delta
Hash-6                84.0 ± 0%      40.0 ± 0%   -52.38%  (p=0.000 n=10+10)
HashMapAcyclic-6       202 ± 0%       202 ± 0%      ~     (all equal)
TailcfgNode-6         11.0 ± 0%       0.0       -100.00%  (p=0.000 n=10+10)

Updates tailscale/corp#2130

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-07-07 11:30:49 -07:00
Brad Fitzpatrick
3962744450 util/deephash: prevent infinite loop on map cycle
Fixes #2340

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-07-07 10:57:46 -07:00
Brad Fitzpatrick
aceaa70b16 util/deephash: move funcs to methods
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-07-07 08:17:18 -07:00
Brad Fitzpatrick
e0258ffd92 util/deephash: use keyed struct literal, fix vet
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-07-05 21:31:30 -07:00
Brad Fitzpatrick
58f2ef6085 util/deephash: add a benchmark and some benchmark data
No code changes.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-07-05 21:21:52 -07:00
Brad Fitzpatrick
9ae3bd0939 util/deephash: export a Hash func for use by the control plane
name              old time/op    new time/op    delta
Hash-6              69.4µs ± 6%    68.4µs ± 4%     ~     (p=0.286 n=9+9)
HashMapAcyclic-6     115µs ± 5%     115µs ± 4%     ~     (p=1.000 n=10+10)

name              old alloc/op   new alloc/op   delta
Hash-6              2.29kB ± 0%    1.88kB ± 0%  -18.13%  (p=0.000 n=10+10)
HashMapAcyclic-6    2.53kB ± 0%    2.53kB ± 0%     ~     (all equal)

name              old allocs/op  new allocs/op  delta
Hash-6                58.0 ± 0%      54.0 ± 0%   -6.90%  (p=0.000 n=10+10)
HashMapAcyclic-6       202 ± 0%       202 ± 0%     ~     (all equal)

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-07-05 11:41:44 -07:00
Brad Fitzpatrick
700badd8f8 util/deephash: move internal/deephash to util/deephash
No code changes. Just a minor package doc addition about lack of API
stability.
2021-07-02 21:33:02 -07:00