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Message-ID: <CAGDMk9EOFenPW2zWAMMkvD2+mV9PLu++mtaw5OVZ=6Q0gZRCLw@mail.gmail.com>
Date: Wed, 8 Apr 2015 15:10:51 -0400
From: John Mudd <johnbmudd@...il.com>
To: musl <musl@...ts.openwall.com>, John Mudd <johnbmudd@...il.com>
Subject: Re: musl perf, 20% slower than native build?
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
$
Here's output from perf record/report for libc. This looks consistent with
the 5% longer run time.
native:
2.20% python libc-2.19.so [.] __memcpy_ssse3
0.85% python libc-2.19.so [.] __x86.get_pc_thunk.bx
0.72% python libc-2.19.so [.] _int_malloc
0.56% python libc-2.19.so [.] __memset_sse2
0.47% python libc-2.19.so [.] _int_free
0.38% python libc-2.19.so [.] malloc
0.25% python libc-2.19.so [.] realloc
0.25% python libc-2.19.so [.] __ctype_b_loc
0.10% python libc-2.19.so [.] free
0.04% python libc-2.19.so [.] __strchr_sse2_bsf
0.03% python libc-2.19.so [.] __memcpy_ia32
0.03% python libc-2.19.so [.] __sbrk
0.03% python libc-2.19.so [.] vfprintf
0.03% python libc-2.19.so [.] mremap_chunk
0.03% python libc-2.19.so [.] __strncpy_ssse3
0.03% python libc-2.19.so [.] __strlen_sse2_bsf
0.03% python libc-2.19.so [.] __x86.get_pc_thunk.cx
musl:
4.74% python libc.so [.] memcpy
2.05% python libc.so [.] free
1.17% python libc.so [.] malloc
1.05% python libc.so [.] unbin
0.90% python libc.so [.] a_and_64
0.81% python libc.so [.] a_or_64
0.68% python libc.so [.] memset
0.31% python libc.so [.] bin_index_up
0.22% python libc.so [.] bin_index
0.22% python libc.so [.] a_ctz_64
0.16% python libc.so [.] realloc
0.16% python libc.so [.] __x86.get_pc_thunk.bx
0.14% python libc.so [.] strlen
0.12% python libc.so [.] trim
0.12% python libc.so [.] strcmp
0.09% python libc.so [.] adjust_size
0.06% python libc.so [.] __strerror_l
0.06% python libc.so [.] __stpncpy
0.03% python libc.so [.] first_set
0.03% python libc.so [.] .L80
0.03% python libc.so [.] remap_rel
0.03% python libc.so [.] find_sym
0.03% python libc.so [.] sysv_hash
0.03% python libc.so [.] fclose
0.03% python libc.so [.] do_relocs
0.03% python libc.so [.] __aio_close
0.03% python libc.so [.] sysv_lookup
On Wed, Apr 8, 2015 at 12:05 PM, Szabolcs Nagy <nsz@...t70.net> wrote:
> 20% is tiny measurement noise compared to the huge
> variance in the environments you are comparing
>
>
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