[issue30040] new empty dict can be more small

[INADA Naoki]

INADA Naoki added the comment:

macro bench result:

$ ./python.default -m perf compare_to -G --min-speed=1 default.json patched.json
Slower (11):
- scimark_lu: 362 ms +- 13 ms -> 383 ms +- 22 ms: 1.06x slower (+6%)
- unpickle_pure_python: 882 us +- 18 us -> 924 us +- 18 us: 1.05x slower (+5%)
- regex_v8: 45.4 ms +- 0.6 ms -> 46.7 ms +- 3.1 ms: 1.03x slower (+3%)
- mako: 40.4 ms +- 0.4 ms -> 41.4 ms +- 0.4 ms: 1.03x slower (+3%)
- meteor_contest: 200 ms +- 1 ms -> 204 ms +- 2 ms: 1.02x slower (+2%)
- genshi_text: 88.8 ms +- 1.2 ms -> 90.1 ms +- 1.6 ms: 1.01x slower (+1%)
- scimark_monte_carlo: 255 ms +- 6 ms -> 258 ms +- 7 ms: 1.01x slower (+1%)
- richards: 176 ms +- 4 ms -> 178 ms +- 8 ms: 1.01x slower (+1%)
- pickle: 24.2 us +- 0.5 us -> 24.4 us +- 0.7 us: 1.01x slower (+1%)
- sympy_str: 438 ms +- 3 ms -> 442 ms +- 3 ms: 1.01x slower (+1%)
- genshi_xml: 196 ms +- 3 ms -> 198 ms +- 2 ms: 1.01x slower (+1%)

Faster (7):
- logging_silent: 746 ns +- 12 ns -> 722 ns +- 11 ns: 1.03x faster (-3%)
- xml_etree_generate: 272 ms +- 4 ms -> 264 ms +- 4 ms: 1.03x faster (-3%)
- telco: 20.7 ms +- 0.7 ms -> 20.2 ms +- 0.4 ms: 1.02x faster (-2%)
- xml_etree_parse: 311 ms +- 13 ms -> 305 ms +- 12 ms: 1.02x faster (-2%)
- nqueens: 266 ms +- 4 ms -> 262 ms +- 2 ms: 1.02x faster (-2%)
- unpack_sequence: 123 ns +- 1 ns -> 122 ns +- 2 ns: 1.01x faster (-1%)
- raytrace: 1.27 sec +- 0.01 sec -> 1.25 sec +- 0.01 sec: 1.01x faster (-1%)

Benchmark hidden because not significant (46)

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue30040>
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