From 7c133fb1094ad1cabbb5cfc157483a43c816c6a9 Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Wed, 1 Jun 2016 16:13:33 +0200 Subject: erts: Change ETS hash load factor from 700% to 200% --- erts/emulator/beam/erl_db_hash.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'erts') diff --git a/erts/emulator/beam/erl_db_hash.c b/erts/emulator/beam/erl_db_hash.c index 74979f984a..4c4ff9b470 100644 --- a/erts/emulator/beam/erl_db_hash.c +++ b/erts/emulator/beam/erl_db_hash.c @@ -95,7 +95,8 @@ /* * The following symbols can be manipulated to "tune" the linear hash array */ -#define CHAIN_LEN 6 /* Medium bucket chain len */ +#define GROW_LIMIT(NACTIVE) ((NACTIVE)*2) +#define SHRINK_LIMIT(NACTIVE) ((NACTIVE) / 2) /* Number of slots per segment */ #define SEGSZ_EXP 8 @@ -463,7 +464,7 @@ db_finalize_dbterm_hash(int cret, DbUpdateHandle* handle); static ERTS_INLINE void try_shrink(DbTableHash* tb) { int nactive = NACTIVE(tb); - if (nactive > SEGSZ && NITEMS(tb) < (nactive * CHAIN_LEN) + if (nactive > SEGSZ && NITEMS(tb) < SHRINK_LIMIT(nactive) && !IS_FIXED(tb)) { shrink(tb, nactive); } @@ -862,7 +863,7 @@ Lnew: WUNLOCK_HASH(lck); { int nactive = NACTIVE(tb); - if (nitems > nactive * (CHAIN_LEN+1) && !IS_FIXED(tb)) { + if (nitems > GROW_LIMIT(nactive) && !IS_FIXED(tb)) { grow(tb, nactive); } } @@ -2250,12 +2251,12 @@ static int db_free_table_continue_hash(DbTable *tbl) done /= 2; while(tb->nslots != 0) { - free_seg(tb, 1); + done += 1 + SEGSZ/64 + free_seg(tb, 1); /* * If we have done enough work, get out here. */ - if (++done >= (DELETE_RECORD_LIMIT / CHAIN_LEN / SEGSZ)) { + if (done >= DELETE_RECORD_LIMIT) { return 0; /* Not done */ } } @@ -2871,7 +2872,7 @@ db_lookup_dbterm_hash(Process *p, DbTable *tbl, Eterm key, Eterm obj, int nitems = erts_smp_atomic_inc_read_nob(&tb->common.nitems); int nactive = NACTIVE(tb); - if (nitems > nactive * (CHAIN_LEN + 1) && !IS_FIXED(tb)) { + if (nitems > GROW_LIMIT(nactive) && !IS_FIXED(tb)) { grow(tb, nactive); } } -- cgit v1.2.3