low-level profiling

[Nicolas Frisby]

I'm way below my depth here, but I'd like to use the perf tool to see where
a program is spending its time.

Unfortunately, the recipe here

http://hackage.haskell.org/trac/ghc/wiki/Debugging/LowLevelProfiling/Perf

isn't working for me. I get output like this instead

90.20%  drbg_test  drbg_test          [.] 0x2515ef
  5.71%  drbg_test  [kernel.kallsyms]  [k] 0xffffffff8103e0ca
  1.53%  drbg_test  libc-2.15.so       [.] bsearch
  1.02%  drbg_test  libc-2.15.so       [.] 0x9194c
  0.43%  drbg_test  libgmp.so.10.0.2   [.] __gmpz_mul_2exp
  0.27%  drbg_test  libgmp.so.10.0.2   [.] __gmpz_add
  0.16%  drbg_test  [vdso]             [.] 0x7fffd3d25983
  0.16%  drbg_test  libgmp.so.10.0.2   [.] __gmpn_lshift
  0.10%  drbg_test  libgmp.so.10.0.2   [.] 0x13565
  0.05%  drbg_test  libgmp.so.10.0.2   [.] __gmpz_init
  0.05%  drbg_test  libc-2.15.so       [.] __select
  0.05%  drbg_test  libgmp.so.10.0.2   [.] __gmpn_modexact_1_odd
  0.05%  drbg_test  libgmp.so.10.0.2   [.] __gmpz_realloc
  0.05%  drbg_test  libc-2.15.so       [.] __errno_location
  0.05%  drbg_test  drbg_test          [.] __gmpz_init at plt
  0.05%  drbg_test  librt-2.15.so      [.] clock_gettime
  0.05%  drbg_test  libgmp.so.10.0.2   [.] __gmpn_add_n

Again --- below my depth here --- but I don't know how to investigate what
0x2515ef indicates. Does anyone have any pointers?

I was hoping that the address would be a nice RTS-ish symbol, like in the
Wiki's examples.

Thanks for your time.
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