On March 13 I raised a concern about performance, Subject "musl 14x slower? ". It now looks like most of that issue had to do with my application code. But here's a more focused look at how musl compares to native build. Granted this is crude, limited, but it looks like musl is 20% slower. I built Python both native and with musl. It's not apples to apples, I actually used a newer version of gcc to build musl 1.1.8 and musl Python. This may and may not be an advantage fro the musl version. I also used -O3 when building musl and musl Python. I assume this should help the musl version. The musl version also uses a newer version of Python. That may or may not be helpful. I can redo with a more consistent builds if this is worthwhile. Maybe you can suggest a straight C benchmark instead. I ran a standard Python benchmark. The code is available here: http://goo.gl/UyLDYC I picked this at random. It is not all encompassing. I've also never used "perf" before. Feel free to advise if this needs improvement. musl version: $ python Python 2.7.9 (default, Apr 2 2015, 15:16:16) [GCC 4.8.2] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> $ perf stat python spitfire_bigtable.py StringIO 507.98 ms cStringIO 189.18 ms list concat 61.59 ms Performance counter stats for '/home/mudd/multicorn_ctree/spitfire_bigtable.py': 810.537826 task-clock (msec) # 0.971 CPUs utilized 297 context-switches # 0.366 K/sec 11 cpu-migrations # 0.014 K/sec 5,977 page-faults # 0.007 M/sec 2,151,830,012 cycles # 2.655 GHz [50.64%] stalled-cycles-frontend stalled-cycles-backend 3,106,074,350 instructions # 1.44 insns per cycle [74.86%] 677,389,217 branches # 835.728 M/sec [74.56%] 13,710,101 branch-misses # 2.02% of all branches [75.09%] 0.834844640 seconds time elapsed $ native: $ python Python 2.7.5 (default, Aug 19 2013, 15:23:53) [GCC 4.7.3] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> $ perf stat ~/multicorn_ctree/spitfire_bigtable.py StringIO 402.63 ms cStringIO 132.62 ms list concat 46.89 ms Performance counter stats for '/home/mudd/multicorn_ctree/spitfire_bigtable.py': 626.547364 task-clock (msec) # 0.982 CPUs utilized 169 context-switches # 0.270 K/sec 19 cpu-migrations # 0.030 K/sec 5,773 page-faults # 0.009 M/sec 1,663,247,805 cycles # 2.655 GHz [49.94%] stalled-cycles-frontend stalled-cycles-backend 2,573,617,826 instructions # 1.55 insns per cycle [75.03%] 554,357,437 branches # 884.781 M/sec [75.49%] 10,851,258 branch-misses # 1.96% of all branches [74.83%] 0.638252827 seconds time elapsed $