[issue29410] Moving to SipHash-1-3

[Inada Naoki]

Inada Naoki <songofacandy at gmail.com> added the comment:

I am not sure this is worth doing.

Microbenchmarks:

## import time

```
$ main/opt/bin/pyperf command main/opt/bin/python3 -c 'import typing,asyncio'
.....................
command: Mean +- std dev: 49.6 ms +- 0.1 ms

$ siphash13/opt/bin/pyperf command siphash13/opt/bin/python3 -c 'import typing,asyncio'
.....................
command: Mean +- std dev: 49.3 ms +- 0.1 ms
```

0.6% faster.

## hash(s+'a')

```
# 6+1
$ siphash13/opt/bin/pyperf timeit --compare-to main/opt/bin/python3 --python-names siphash24:siphash13 -s 'b=b"x"*6' -- 'hash(b+b"a")'
siphash24: ..................... 87.7 ns +- 2.8 ns
siphash13: ..................... 84.8 ns +- 1.6 ns

Mean +- std dev: [siphash24] 87.7 ns +- 2.8 ns -> [siphash13] 84.8 ns +- 1.6 ns: 1.03x faster

# 6000+1
$ siphash13/opt/bin/pyperf timeit --compare-to main/opt/bin/python3 --python-names siphash24:siphash13 -s 'b=b"x"*6000' -- 'hash(b+b"a")'
siphash24: ..................... 2.98 us +- 0.03 us
siphash13: ..................... 1.67 us +- 0.03 us

Mean +- std dev: [siphash24] 2.98 us +- 0.03 us -> [siphash13] 1.67 us +- 0.03 us: 1.78x faster
```

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<https://bugs.python.org/issue29410>
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