[issue33597] Compact PyGC_Head

[Antoine Pitrou]

Antoine Pitrou <pitrou at free.fr> added the comment:

Ok, I ran a subset of the benchmarks to record their memory footprint and got these results:

master-mem.perf
===============

Performance version: 0.6.2
Python version: 3.8.0a0 (64-bit) revision 73cbe7a
Report on Linux-4.15.0-22-generic-x86_64-with-glibc2.9
Number of logical CPUs: 16
Start date: 2018-05-29 16:54:24.964539
End date: 2018-05-29 17:04:05.608437

methane-mem.perf
================

Performance version: 0.6.2
Python version: 3.8.0a0 (64-bit) revision 16c66ca
Report on Linux-4.15.0-22-generic-x86_64-with-glibc2.9
Number of logical CPUs: 16
Start date: 2018-05-29 17:15:00.936857
End date: 2018-05-29 17:24:33.755119

+------------------------+-----------------+------------------+---------------+------------------------+
| Benchmark              | master-mem.perf | methane-mem.perf | Change        | Significance           |
+========================+=================+==================+===============+========================+
| 2to3                   | 7121.8 kB       | 6944.4 kB        | 1.03x smaller | Significant (t=31.59)  |
+------------------------+-----------------+------------------+---------------+------------------------+
| chameleon              | 15.7 MB         | 15.3 MB          | 1.02x smaller | Significant (t=24.25)  |
+------------------------+-----------------+------------------+---------------+------------------------+
| html5lib               | 20.1 MB         | 19.4 MB          | 1.04x smaller | Significant (t=67.15)  |
+------------------------+-----------------+------------------+---------------+------------------------+
| json_dumps             | 8282.2 kB       | 8021.4 kB        | 1.03x smaller | Significant (t=234.01) |
+------------------------+-----------------+------------------+---------------+------------------------+
| json_loads             | 7671.2 kB       | 7494.0 kB        | 1.02x smaller | Significant (t=37.43)  |
+------------------------+-----------------+------------------+---------------+------------------------+
| pickle                 | 7883.4 kB       | 7698.6 kB        | 1.02x smaller | Significant (t=28.64)  |
+------------------------+-----------------+------------------+---------------+------------------------+
| pickle_pure_python     | 7867.4 kB       | 7680.0 kB        | 1.02x smaller | Significant (t=48.64)  |
+------------------------+-----------------+------------------+---------------+------------------------+
| sqlalchemy_declarative | 18.4 MB         | 17.9 MB          | 1.03x smaller | Significant (t=132.47) |
+------------------------+-----------------+------------------+---------------+------------------------+
| sqlalchemy_imperative  | 17.8 MB         | 17.3 MB          | 1.03x smaller | Significant (t=128.94) |
+------------------------+-----------------+------------------+---------------+------------------------+
| tornado_http           | 24.5 MB         | 24.0 MB          | 1.02x smaller | Significant (t=7.99)   |
+------------------------+-----------------+------------------+---------------+------------------------+
| unpickle               | 7883.2 kB       | 7694.2 kB        | 1.02x smaller | Significant (t=31.19)  |
+------------------------+-----------------+------------------+---------------+------------------------+
| unpickle_pure_python   | 7891.6 kB       | 7699.4 kB        | 1.02x smaller | Significant (t=63.68)  |
+------------------------+-----------------+------------------+---------------+------------------------+
| xml_etree_generate     | 12.0 MB         | 11.5 MB          | 1.04x smaller | Significant (t=26.07)  |
+------------------------+-----------------+------------------+---------------+------------------------+
| xml_etree_iterparse    | 11.8 MB         | 11.3 MB          | 1.04x smaller | Significant (t=146.82) |
+------------------------+-----------------+------------------+---------------+------------------------+
| xml_etree_parse        | 11.6 MB         | 11.2 MB          | 1.03x smaller | Significant (t=116.08) |
+------------------------+-----------------+------------------+---------------+------------------------+
| xml_etree_process      | 12.3 MB         | 12.0 MB          | 1.02x smaller | Significant (t=49.04)  |
+------------------------+-----------------+------------------+---------------+------------------------+

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue33597>
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