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@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.