Commit Graph

3 Commits (32a1a3d1c03de7c7a036ce7eefc0ac0599325bb4)

Author SHA1 Message Date
Joe Tsai 1f7479466e
util/deephash: use sha256x (#5339)
Switch deephash to use sha256x.Hash.

We add sha256x.HashString to efficiently hash a string.
It uses unsafe under the hood to convert a string to a []byte.
We also modify sha256x.Hash to export the underlying hash.Hash
for testing purposes so that we can intercept all hash.Hash calls.

Performance:

	name                 old time/op    new time/op    delta
	Hash-24                19.8µs ± 1%    19.2µs ± 1%  -3.01%  (p=0.000 n=10+10)
	HashPacketFilter-24    2.61µs ± 0%    2.53µs ± 1%  -3.01%  (p=0.000 n=8+10)
	HashMapAcyclic-24      31.3µs ± 1%    29.8µs ± 0%  -4.80%  (p=0.000 n=10+9)
	TailcfgNode-24         1.83µs ± 1%    1.82µs ± 2%    ~     (p=0.305 n=10+10)
	HashArray-24            344ns ± 2%     323ns ± 1%  -6.02%  (p=0.000 n=9+10)

The performance gains is not as dramatic as sha256x over sha256 due to:
1. most of the hashing already occurring through the direct memory hashing logic, and
2. what does not go through direct memory hashing is slowed down by reflect.

Signed-off-by: Joe Tsai <joetsai@digital-static.net>
2 years ago
Joe Tsai 1c3c6b5382
util/sha256x: make Hash.Sum non-escaping (#5338)
Since Hash is a concrete type, we can make it such that
Sum never escapes the input.

Signed-off-by: Joe Tsai <joetsai@digital-static.net>
2 years ago
Joe Tsai 76b0e578c5
util/sha256x: new package (#5337)
The hash.Hash provided by sha256.New is much more efficient
if we always provide it with data a multiple of the block size.
This avoids double-copying of data into the internal block
of sha256.digest.x. Effectively, we are managing a block ourselves
to ensure we only ever call hash.Hash.Write with full blocks.

Performance:

	name    old time/op    new time/op    delta
	Hash    33.5µs ± 1%    20.6µs ± 1%  -38.40%  (p=0.000 n=10+9)

The logic has gone through CPU-hours of fuzzing.

Signed-off-by: Joe Tsai <joetsai@digital-static.net>
2 years ago