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/emulator/beam/erl_db_hash.c') 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 From f4bdac18cb9dd45185e911308a5ebd95ff10d7fd Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Wed, 1 Jun 2016 16:19:04 +0200 Subject: erts: Remove unnecessary access of 'is_resizing' in tables without write_concurrency and remove it totally #ifndef ERTS_SMP --- erts/emulator/beam/erl_db_hash.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) (limited to 'erts/emulator/beam/erl_db_hash.c') diff --git a/erts/emulator/beam/erl_db_hash.c b/erts/emulator/beam/erl_db_hash.c index 4c4ff9b470..074ac6d64e 100644 --- a/erts/emulator/beam/erl_db_hash.c +++ b/erts/emulator/beam/erl_db_hash.c @@ -671,8 +671,8 @@ int db_create_hash(Process *p, DbTable *tbl) tb->nsegs = NSEG_1; tb->nslots = SEGSZ; - erts_smp_atomic_init_nob(&tb->is_resizing, 0); #ifdef ERTS_SMP + erts_smp_atomic_init_nob(&tb->is_resizing, 0); if (tb->common.type & DB_FINE_LOCKED) { erts_smp_rwmtx_opt_t rwmtx_opt = ERTS_SMP_RWMTX_OPT_DEFAULT_INITER; int i; @@ -2605,23 +2605,22 @@ static Eterm build_term_list(Process* p, HashDbTerm* ptr1, HashDbTerm* ptr2, static ERTS_INLINE int begin_resizing(DbTableHash* tb) { +#ifdef ERTS_SMP if (DB_USING_FINE_LOCKING(tb)) - return !erts_smp_atomic_xchg_acqb(&tb->is_resizing, 1); - else { - if (erts_smp_atomic_read_nob(&tb->is_resizing)) - return 0; - erts_smp_atomic_set_nob(&tb->is_resizing, 1); - return 1; - } + return !erts_atomic_xchg_acqb(&tb->is_resizing, 1); + else + ERTS_LC_ASSERT(erts_lc_rwmtx_is_rwlocked(&tb->common.rwlock)); +#endif + return 1; } static ERTS_INLINE void done_resizing(DbTableHash* tb) { +#ifdef ERTS_SMP if (DB_USING_FINE_LOCKING(tb)) - erts_smp_atomic_set_relb(&tb->is_resizing, 0); - else - erts_smp_atomic_set_nob(&tb->is_resizing, 0); + erts_atomic_set_relb(&tb->is_resizing, 0); +#endif } /* Grow table with one new bucket. -- cgit v1.2.3