[Python-Dev] A new dict for Xmas? (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Fri Dec 16 00:15:16 CET 2011

On Thu, 15 Dec 2011 22🔞18 +0000 Mark Shannon <mark at hotpy.org> wrote:

For the gcbench benchmark (from unladen swallow), cpython with the new dict is about 9% faster and, more importantly, reduces memory use from 99 Mbytes to 61Mbytes (a 38% reduction). All tests were done on my ancient 32 bit intel linux machine, please try it out on your machines and let me know what sort of results you get.

Benchmark results under a Core i5, 64-bit Linux:

Report on Linux localhost.localdomain 2.6.38.8-desktop-8.mga #1 SMP Fri Nov 4 00:05:53 UTC 2011 x86_64 x86_64 Total CPU cores: 4

call_method

Min: 0.292352 -> 0.274041: 1.07x faster Avg: 0.292978 -> 0.277124: 1.06x faster Significant (t=17.31) Stddev: 0.00053 -> 0.00351: 6.5719x larger

call_method_slots

Min: 0.284101 -> 0.273508: 1.04x faster Avg: 0.285029 -> 0.274534: 1.04x faster Significant (t=26.86) Stddev: 0.00068 -> 0.00135: 1.9969x larger

call_simple

Min: 0.225191 -> 0.222104: 1.01x faster Avg: 0.227443 -> 0.222776: 1.02x faster Significant (t=9.53) Stddev: 0.00181 -> 0.00056: 3.2266x smaller

fastpickle

Min: 0.482402 -> 0.493695: 1.02x slower Avg: 0.486077 -> 0.496568: 1.02x slower Significant (t=-5.35) Stddev: 0.00340 -> 0.00276: 1.2335x smaller

fastunpickle

Min: 0.394846 -> 0.433733: 1.10x slower Avg: 0.397362 -> 0.436318: 1.10x slower Significant (t=-23.73) Stddev: 0.00234 -> 0.00283: 1.2129x larger

float

Min: 0.052567 -> 0.051377: 1.02x faster Avg: 0.053812 -> 0.052669: 1.02x faster Significant (t=3.72) Stddev: 0.00110 -> 0.00107: 1.0203x smaller

json_dump

Min: 0.381395 -> 0.391053: 1.03x slower Avg: 0.381937 -> 0.393219: 1.03x slower Significant (t=-7.15) Stddev: 0.00043 -> 0.00350: 8.1447x larger

json_load

Min: 0.347112 -> 0.369763: 1.07x slower Avg: 0.347490 -> 0.370317: 1.07x slower Significant (t=-69.64) Stddev: 0.00045 -> 0.00058: 1.2717x larger

nbody

Min: 0.238068 -> 0.219208: 1.09x faster Avg: 0.238951 -> 0.220000: 1.09x faster Significant (t=36.09) Stddev: 0.00076 -> 0.00090: 1.1863x larger

nqueens

Min: 0.262282 -> 0.252576: 1.04x faster Avg: 0.263835 -> 0.254497: 1.04x faster Significant (t=7.12) Stddev: 0.00117 -> 0.00269: 2.2914x larger

regex_effbot

Min: 0.060298 -> 0.057791: 1.04x faster Avg: 0.060435 -> 0.058128: 1.04x faster Significant (t=17.82) Stddev: 0.00012 -> 0.00026: 2.1761x larger

richards

Min: 0.148266 -> 0.143755: 1.03x faster Avg: 0.150677 -> 0.145003: 1.04x faster Significant (t=5.74) Stddev: 0.00200 -> 0.00094: 2.1329x smaller

silent_logging

Min: 0.057191 -> 0.059082: 1.03x slower Avg: 0.057335 -> 0.059194: 1.03x slower Significant (t=-17.40) Stddev: 0.00020 -> 0.00013: 1.4948x smaller

unpack_sequence

Min: 0.000046 -> 0.000042: 1.10x faster Avg: 0.000048 -> 0.000044: 1.09x faster Significant (t=128.98) Stddev: 0.00000 -> 0.00000: 1.8933x smaller

gcbench first showed no memory consumption difference (using "ps -u"). I then removed the "stretch tree" (which apparently reserves memory upfront) and I saw a ~30% memory saving as well as a 20% performance improvement on large sizes.

Regards

Antoine.

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