On Fri, Feb 15, 2013 at 10:05 AM, Nicolas Frisby <nicolas.fri...@gmail.com>wrote:
> 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. > I thought I fixed this issue (at least in the native backend). What was missing before was .size assembler directives that would let tools like perf know where a function started and ended. See this commit https://github.com/ghc/ghc/commit/32f24ddfd9549010dd345733c6f46f67196cacf6 Perhaps it broke at some point? Are you using the x86 backend?
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