Here's a fresh native compile of the same version of Python, same gcc. Now the musl version is only slightly slower, maybe 5%. BTW, I'm not complaining. I use musl for portability, not speed.
$ python
Python 2.7.9 (default, Apr 8 2015, 14:29:14)
[GCC 4.8.2] on linux2
>>>
$ perf stat ~/multicorn_ctree/spitfire_bigtable.py
StringIO 523.62 ms
cStringIO 144.32 ms
list concat 55.12 ms
Performance counter stats for '/home/mudd/multicorn_ctree/spitfire_bigtable.py':
769.874633 task-clock (msec) # 0.977 CPUs utilized
269 context-switches # 0.349 K/sec
6 cpu-migrations # 0.008 K/sec
5,997 page-faults # 0.008 M/sec
2,043,153,669 cycles # 2.654 GHz [50.74%]
<not supported> stalled-cycles-frontend
<not supported> stalled-cycles-backend
2,993,940,382 instructions # 1.47 insns per cycle [75.11%]
673,064,696 branches # 874.252 M/sec [74.59%]
15,486,299 branch-misses # 2.30% of all branches [74.71%]
0.787704322 seconds time elapsed
$