From c5a826b3d3a80726473fd9c2a7bea58b4363a993 Mon Sep 17 00:00:00 2001 From: Victor Ren Date: Thu, 6 Oct 2016 18:27:07 +0800 Subject: Use atom value as hash value in process dictionary In the origin implementation, the hash value of atom term is retrieved from the atom table. Reading the atom table is expensive since it is in memory and leads to more cache missing. The size of a process dictionary is usually small. The atom value (the index) is unique and can be hash value for it. Using the atom value directly should be more efficient. --- erts/emulator/beam/beam_load.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'erts/emulator/beam/beam_load.c') diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c index d69b18e22f..8aecf01bfd 100644 --- a/erts/emulator/beam/beam_load.c +++ b/erts/emulator/beam/beam_load.c @@ -4345,7 +4345,7 @@ hash_internal_genop_arg(LoaderState* stp, GenOpArg Key, Uint32* hx) { switch (Key.type) { case TAG_a: - *hx = atom_tab(atom_val(Key.val))->slot.bucket.hvalue; + *hx = atom_val(Key.val); return 1; case TAG_i: *hx = Key.val; -- cgit v1.2.3 From b1070efa22f18e19bc7c55fd69e0796f48abf256 Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Mon, 10 Oct 2016 15:05:26 +0200 Subject: erts: Refactor process dict hash pre-calculation with new function erts_pd_make_hx() --- erts/emulator/beam/beam_load.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) (limited to 'erts/emulator/beam/beam_load.c') diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c index 8aecf01bfd..165328f992 100644 --- a/erts/emulator/beam/beam_load.c +++ b/erts/emulator/beam/beam_load.c @@ -39,6 +39,7 @@ #include "erl_binary.h" #include "erl_zlib.h" #include "erl_map.h" +#include "erl_process_dict.h" #ifdef HIPE #include "hipe_bif0.h" @@ -4343,22 +4344,25 @@ gen_get_map_element(LoaderState* stp, GenOpArg Fail, GenOpArg Src, static int hash_internal_genop_arg(LoaderState* stp, GenOpArg Key, Uint32* hx) { + Eterm key_term; switch (Key.type) { case TAG_a: - *hx = atom_val(Key.val); - return 1; + key_term = Key.val; + break; case TAG_i: - *hx = Key.val; - return 1; + key_term = make_small(Key.val); + break; case TAG_n: - *hx = make_internal_hash(NIL); - return 1; + key_term = NIL; + break; case TAG_q: - *hx = make_internal_hash(stp->literals[Key.val].term); - return 1; + key_term = stp->literals[Key.val].term; + break; default: return 0; } + *hx = erts_pd_make_hx(key_term); + return 1; } -- cgit v1.2.3